Composite material, middle frame, preparation method of middle frame and electronic equipment

Abstract

The embodiment of the invention provides a composite material, a middle frame, a preparation method of the middle frame and electronic equipment, and relates to the technical field of terminals. The composite material comprises a shell and a first filling body, and a first containing channel is defined by the shell; the first filling body is arranged in the first containing channel, the first filling body is combined with the inner wall of the first containing channel, and combination comprises metallurgical combination. The shell and the first filling body can be combined in a metallurgical bonding mode, and the bonding force between the shell and the first filling body can be increased, so that the composite material has high strength. Furthermore, after the middle frame is prepared from the composite material, the connection reliability of the middle frame is relatively high.

Description

Technical Field

[0001] The present application relates to the technical field of terminals, and particularly to a composite material, a middle frame, a preparation method thereof, and an electronic device. Background Art

[0002] With the development of electronic technology, electronic devices such as mobile phones or tablet computers have become one of the indispensable products in people's lives. Taking a mobile phone as an example, a mobile phone may include components such as a middle frame, a display screen, and a rear cover. The rear cover and the display screen are respectively located on both sides of the middle frame, and enclose an internal space of the mobile phone with the middle frame. The internal space can also accommodate internal components such as a memory card, a battery, and a processor of the mobile phone.

[0003] In the related art, the frame of the middle frame is made of stainless steel or titanium alloy, and the middle plate is made of aluminum alloy, and the frame and the middle plate are connected by welding or riveting. In this way, the connection reliability between the frame and the middle plate is relatively low, affecting the overall stiffness of the middle frame. Summary of the Invention

[0004] The present application provides a composite material, a middle frame, a preparation method thereof, and an electronic device. The outer shell and the first filler in the composite material are combined by a metallurgical bonding method, and after the middle frame is prepared by using the composite material, the connection reliability of the middle frame is relatively high.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] In a first aspect, a composite material is provided, including: an outer shell and a first filler, the outer shell enclosing a first accommodation channel; the first filler is disposed in the first accommodation channel, and the first filler is combined with the inner wall of the first accommodation channel, and the combination includes metallurgical bonding.

[0007] In this way, the outer shell and the first filler can be combined by a metallurgical bonding method, which can increase the bonding force between the two, so that the composite material has a relatively high strength. Furthermore, after the middle frame is prepared by using the composite material, the connection reliability of the middle frame is relatively high.

[0008] In an implementable manner, the outer shell and the first filler are further connected by mutually engaging protrusions and grooves.

[0009] In this way, the first filler and the outer shell can be connected by mutually engaging protrusions and grooves, and the combination method of the two can be partial metallurgical bonding and partial mechanical bonding. It can increase the bonding force between the two, so that the composite material has a relatively high strength. Furthermore, after the middle frame is prepared by using the composite material, the connection reliability is relatively high, improving the overall rigidity of the middle frame.

[0010] In an implementable manner, the protrusions are arranged on the inner wall of the first accommodating channel, and the grooves are arranged on the outer wall of the first filling body, and an interference fit is provided between the protrusions and the grooves.

[0011] In this way, the protrusions on the inner wall of the first accommodating channel can be combined with the grooves on the outer wall of the first filling body through extrusion. The combination method of the two can be partial metallurgical bonding and partial mechanical bonding, which can generate a large bonding force between the outer shell and the first filling body, and the two can be closely combined. Thus, the strength of the composite material is improved. Furthermore, after using this composite material to prepare the middle frame, the connection reliability is relatively high.

[0012] In an implementable manner, the protrusion includes a first surface and a second surface which are oppositely arranged. Both the first surface and the second surface are arranged parallel to the center line of the first accommodating channel. One end of the first surface and the second surface is connected to the inner wall of the outer shell, and the other ends of the first surface and the second surface intersect or are parallel.

[0013] By providing the protrusion and including the first surface and the second surface in the protrusion, the contact area between the outer shell and the first filling body can be increased, so that a large bonding force is generated between the outer shell and the first filling body, thereby improving the strength of the composite material.

[0014] In an implementable manner, both the protrusions and the grooves are multiple, and each protrusion is fitted with a groove.

[0015] In this way, by uniformly arranging multiple protrusions on the inner wall of the outer shell, the entire outer shell structure can be made more stable. Thus, after being fitted with multiple grooves later, a large bonding force is ensured, making the composite material have a relatively high strength.

[0016] In an implementable manner, the outer shell includes at least one of pure titanium, titanium alloy, stainless steel, and alloy steel. Using at least one of pure titanium, titanium alloy, stainless steel, and alloy steel with a relatively high elastic modulus can improve the elastic modulus and overall rigidity of the composite material. Furthermore, after using this composite material to prepare the middle frame, the connection reliability is relatively high, and the overall rigidity of the middle frame is improved.

[0017] In an implementable manner, the first filling body includes a hard aluminum alloy, and the Vickers hardness of the hard aluminum alloy is greater than or equal to 120 HV. Using a hard aluminum alloy with a relatively high hardness for the first filling body can improve the hardness of the composite material. Furthermore, after using this composite material to prepare the middle frame, the connection reliability is relatively high, and the overall hardness of the middle frame is improved.

[0018] In an implementable manner, the first filler includes a decorative anodized aluminum alloy. By using a decorative anodized aluminum alloy with a relatively high elastic modulus for the first filler, the elastic modulus and overall rigidity of the composite material can be improved. Furthermore, after using this composite material to prepare the middle frame, the connection reliability is relatively high, enhancing the overall rigidity of the middle frame.

[0019] In an implementable manner, the first filler includes a first aluminum matrix composite material, and the first aluminum matrix composite material includes pure aluminum or an aluminum alloy, and at least one of the following: silicon carbide, aluminum oxide, boron carbide, titanium diboride, graphene, carbon nanotubes, graphite, and diamond. By using an aluminum matrix composite material with a relatively high elastic modulus for the first filler, the elastic modulus and overall rigidity of the composite material can be improved. Furthermore, after using this composite material to prepare the middle frame, the connection reliability is relatively high, enhancing the overall rigidity of the middle frame.

[0020] In an implementable manner, the mass percentage of silicon carbide in the first aluminum matrix composite material is less than 65% of the first aluminum matrix composite material.

[0021] In this way, by controlling the content of silicon carbide in the first aluminum matrix composite material, the content of silicon carbide doped in the aluminum alloy can be made more appropriate, thereby enhancing the elastic modulus and anti-bending ability of the first aluminum matrix composite material.

[0022] In an implementable manner, the silicon carbide in the first aluminum matrix composite material includes sub-micron-sized first silicon carbide particles and micron-sized first silicon carbide particles;

[0023] Among them, the mass percentage of the sub-micron-sized first silicon carbide particles in the first aluminum matrix composite material is 0 - 20%, and the mass percentage of the micron-sized first silicon carbide particles in the first aluminum matrix composite material is 5% - 40%.

[0024] Specifically, in the cumulative particle size distribution of the sub-micron-sized first silicon carbide particles, D50 is 0.3 microns - 1.0 micron, in the cumulative particle size distribution of the micron-sized silicon carbide particles, D50 is 3 microns - 20 microns, and in the cumulative particle size distribution of the aluminum alloy, D50 is less than or equal to 20 microns.

[0025] In this way, by controlling the content of the sub-micron-sized first silicon carbide particles and the micron-sized first silicon carbide particles in the first aluminum matrix composite material, the content of silicon carbide doped in the aluminum alloy can be made more appropriate, thereby enhancing the elastic modulus and anti-bending ability of the first aluminum matrix composite material.

[0026] In an implementable manner, the composite material further includes a second filler. A second accommodation channel is provided in the first filler, and the center line of the second accommodation channel is parallel to the center line of the first accommodation channel; the second filler is disposed in the second accommodation channel, and the second filler is combined with the first filler, and the combination includes metallurgical bonding.

[0027] The first filler and the second filler can be combined by metallurgical bonding, which can increase the bonding force between the two, so that the composite material has higher strength. At the same time, after using the composite material including the first filler, the second filler and the outer shell to prepare the middle frame, the anti-bending ability, the overall drop anti-deformation ability and the strength of the entire middle frame can be improved.

[0028] In an implementable manner, the second filler includes a second aluminum matrix composite material, and the mass percentage of silicon carbide in the second aluminum matrix composite material is less than 65%.

[0029] In this way, by the content of silicon carbide in the second aluminum matrix composite material, the content of silicon carbide doped in the aluminum alloy can be made more appropriate, thereby improving the elastic modulus and anti-bending ability of the second aluminum matrix composite material.

[0030] In an implementable manner, the silicon carbide in the second aluminum matrix composite material includes sub-micron second silicon carbide particles and micron second silicon carbide particles;

[0031] Among them, the mass percentage of the sub-micron second silicon carbide particles in the second aluminum matrix composite material is 0-10%, and the mass percentage of the micron second silicon carbide particles in the second aluminum matrix composite material is 15%-50%. In the cumulative particle size distribution of the sub-micron second silicon carbide particles, D50 is 0.5 micron - 1.0 micron, and in the cumulative particle size distribution of the micron second silicon carbide particles, D50 is 3 microns - 20 microns.

[0032] By controlling the content of the sub-micron second silicon carbide particles and the micron second silicon carbide particles in the second aluminum matrix composite material, the content of silicon carbide doped in the aluminum alloy can be made more appropriate, thereby improving the higher elastic modulus and anti-bending ability of the second aluminum matrix composite material.

[0033] In an implementable manner, the elastic modulus of the first filler is greater than or equal to 85 GPa, and the elastic modulus of the second filler is greater than or equal to 110 GPa.

[0034] In an implementable manner, the elongation of the first filler is greater than 3%, and the elongation of the second filler is greater than 0.2%.

[0035] The first filler provided by the embodiments of the present application has a relatively high elastic modulus, which can improve the overall rigidity of the composite material and the rigidity of the prepared middle frame. In addition, the first filler has a relatively high elongation rate, that is, it has a strong plastic deformation ability. It can improve the processing diversity of the composite material and the processing diversity of the prepared middle frame.

[0036] At the same time, the second fillers all have a relatively high elastic modulus, and the elastic modulus of the second fillers is higher than that of the first filler. The composite material prepared by using the first filler and the second fillers also has a relatively high elastic modulus, which can improve the overall rigidity of the composite material. At the same time, the second fillers all have a relatively high elongation rate. In this way, the composite material prepared by using the first filler and the second fillers has a strong plastic deformation ability and a relatively high processing diversity.

[0037] In a second aspect, the embodiments of the present application further provide a method for preparing a composite material. The method includes:

[0038] Prepare a housing, and the housing encloses a first accommodation channel. Prepare a first filler and install the first filler in the first accommodation channel. The first filler is combined with the inner wall of the first accommodation channel, and the combination includes metallurgical bonding.

[0039] In this way, the prepared housing and the first filler can be combined by means of metallurgical bonding, which can increase the bonding force between the two, so that the composite material has a relatively high strength. Furthermore, after using the composite material to prepare a middle frame, the connection reliability is relatively high.

[0040] In a feasible manner, installing the first filler in the first accommodation channel includes: extruding the housing and the first filler, and the housing and the first filler are connected by mutually engaged protrusions and grooves, so that the housing and the first filler are in interference fit.

[0041] In this way, by extruding the first filler and the housing, the two can be connected by mutually engaged protrusions and grooves, and the combination method can be partial metallurgical bonding and partial mechanical bonding. It can increase the bonding force between the two, so that the composite material has a relatively high strength. Furthermore, after using the composite material to prepare a middle frame, the connection reliability is relatively high, and the overall rigidity of the middle frame is improved.

[0042] In a feasible manner, extruding the housing and the first filler includes: performing isostatic pressing on the housing and the first filler.

[0043] By performing isostatic pressing on the housing and the first filler, it can make the prepared composite material have excellent performance and a short production cycle.

[0044] In an implementable manner, isostatic pressing is performed on the outer shell and the first filler, including: extruding according to a predetermined extrusion ratio, and heating the outer shell and the first filler while extruding.

[0045] By extruding according to a predetermined extrusion ratio and heating the outer shell and the first filler while extruding, the outer shell and the first filler can be fully combined, ensuring that the prepared composite material has high strength. Furthermore, after using the composite material to prepare the middle frame, the connection reliability is high, enhancing the overall rigidity of the middle frame.

[0046] In an implementable manner, preparing the outer shell includes: providing a first rod, forming a first accommodating channel in the first rod, and the center line of the first accommodating channel is parallel to the center line of the first rod; forming a protrusion on the inner wall of the first accommodating channel, and the protrusion extends along a direction parallel to the center line of the first rod.

[0047] Preparing the first filler includes: providing a second rod, forming a groove on the outer wall of the second rod, and the groove extends along a direction parallel to the center line of the second rod. Installing the first filler in the first accommodating channel further includes: inserting the second rod into the first accommodating channel along a direction parallel to the center line of the first rod, and embedding the protrusion into the groove.

[0048] In this way, by providing a protrusion on the inner wall of the first accommodating channel and a groove on the outer wall of the first filler, the bonding method between the first filler and the outer shell can be partial metallurgical bonding and partial mechanical bonding, which can increase the bonding force between the two, and the two can be tightly bonded. Thus, the strength of the composite material is improved. Furthermore, after using the composite material to prepare the middle frame, the connection reliability is high.

[0049] In an implementable manner, preparing the first filler further includes: forming a second accommodating channel in the first filler, and the center line of the second accommodating channel is parallel to the center line of the first accommodating channel.

[0050] The method further includes: preparing a second filler, installing the second filler in the second accommodating channel, and bonding the second filler to the second accommodating channel, and the bonding includes metallurgical bonding.

[0051] By preparing the second filler and installing the second filler in the second accommodating channel, the first filler and the second filler can be bonded by metallurgical bonding, which can increase the bonding force between the two, so that the composite material has high strength. At the same time, after using the composite material including the first filler, the second filler and the outer shell to prepare the middle frame, the anti-bending ability, the overall drop anti-deformation ability and the strength of the entire middle frame can be improved.

[0052] In a third aspect, an embodiment of the present application further provides a middle frame made of the composite material of the first aspect. The middle frame includes a frame and a middle plate. The middle plate is connected to the frame and is configured to be disposed inside the electronic device; the frame includes a housing, and the middle plate includes a first filler.

[0053] The frame part of the middle frame includes a housing, and the middle plate part includes a first filler. On the one hand, the first filler can be made of a first aluminum matrix composite material, an anodized aluminum alloy or a hard aluminum alloy, which has a relatively high elastic modulus and relatively high hardness, improving the anti-bending ability and the overall drop anti-deformation ability of the entire middle frame, thereby enhancing the strength of the entire middle frame. On the other hand, the corresponding thickness of the middle plate can be thinned, reducing the battery area in the middle frame where the battery is disposed, enabling a larger-capacity battery to be placed, and thus contributing more battery capacity. On yet another hand, the frame and the middle plate in the middle frame are integrally formed, with relatively high connection reliability, enhancing the overall stiffness of the middle frame.

[0054] In an implementable manner, the composite material further includes a second filler. A second accommodation channel is provided in the first filler, and the center line of the second accommodation channel is parallel to the center line of the first accommodation channel; the second filler is disposed in the second accommodation channel, and the second filler is combined with the first filler, and the combination includes metallurgical bonding.

[0055] The middle plate includes a battery area and a non-battery area. The battery area includes the second filler, and the non-battery area includes the first filler.

[0056] The battery area in the middle plate includes the second filler, and the non-battery area includes the first filler. The elastic modulus of the second filler corresponding to the second aluminum matrix composite material is higher than the elastic modulus of the first filler corresponding to the first aluminum matrix composite material. It can provide more reliable protection for the battery, thereby improving the user experience.

[0057] In a fourth aspect, an embodiment of the present application further provides a middle frame made of the composite material of the first aspect. The middle frame includes a frame and a rear cover. The frame is connected to the rear cover, and the rear cover is configured to be located on the back of the electronic device; the frame includes a housing, and the rear cover includes a first filler.

[0058] The frame part of the middle frame includes a housing, and the rear cover part includes a first filler. On the one hand, the first filler can be made of a first aluminum matrix composite material, an anodized aluminum alloy or a hard aluminum alloy, which has a relatively high elastic modulus and relatively high hardness, improving the anti-bending ability and the overall drop anti-deformation ability of the entire middle frame, thereby enhancing the strength of the entire middle frame. On the other hand, the corresponding thickness of the rear cover can be thinned, reducing the battery area in the middle frame where the battery is disposed, enabling a larger-capacity battery to be placed, and thus contributing more battery capacity. On yet another hand, the frame and the rear cover in the middle frame are integrally formed, with relatively high connection reliability, enhancing the overall stiffness of the middle frame.

[0059] In an implementable manner, the composite material further includes a second filler body. A second accommodation channel is provided in the first filler body, and the center line of the second accommodation channel is parallel to the center line of the first accommodation channel; the second filler body is arranged in the second accommodation channel, and the second filler body is combined with the first filler body, and the combination includes metallurgical bonding.

[0060] The rear cover includes a battery area and a non-battery area. The battery area includes the second filler body, and the non-battery area includes the first filler body. At least part of the outer surface of the rear cover is provided with a decorative layer, and the decorative layer is made of anodized aluminum alloy.

[0061] The battery area in the rear cover includes the second filler body, and the non-battery area includes the first filler body. The elastic modulus of the second filler body corresponding to the second aluminum matrix composite material is higher than the elastic modulus of the first filler body corresponding to the first aluminum matrix composite material. It can provide more reliable protection for the battery, thereby improving the user experience.

[0062] Meanwhile, at least part of the outer surface of the rear cover is provided with a decorative layer. The decorative layer not only has a good decorative effect, but also is not easily damaged, has good integrity, can prevent the metal material inside the middle frame from being oxidized, and realizes effective protection for the metal material inside the middle frame.

[0063] In a fifth aspect, an embodiment of the present application further provides a method for preparing a middle frame. The method includes: preparing a composite material by using the method for preparing the composite material described in the second aspect. Cutting the composite material along a square perpendicular to the center line of the first accommodation channel to form a plate body, and machining the plate body so that the outer shell forms the frame of the middle frame, and the first filler body forms the middle plate of the middle frame.

[0064] In a sixth aspect, an embodiment of the present application further provides a method for preparing a middle frame. The method includes: preparing a composite material by using the method for preparing the composite material described in the second aspect. Cutting the composite material along a square perpendicular to the center line of the first accommodation channel to form a plate body, and machining the plate body so that the outer shell forms the frame of the middle frame, and the first filler body forms the rear cover of the middle frame.

[0065] In an implementable manner, when machining the plate body so that the outer shell forms the frame of the middle frame and the first filler body forms the rear cover of the middle frame, it further includes: anodizing at least part of the outer surface of the rear cover to obtain a decorative layer.

[0066] In a seventh aspect, an embodiment of the present application further provides an electronic device. The electronic device includes a display screen, a battery, and the middle frame described in the third aspect, or the middle frame described in the fourth aspect. The display screen and the battery are arranged on the middle frame. Description of the Drawings

[0067] Figure 1 Schematic diagram of the structure of a middle frame provided by an embodiment of the present application;

[0068] Figure 2 Schematic diagram of a scenario of a mobile phone being bent and deformed provided by an embodiment of the present application;

[0069] Figure 3 Schematic diagram of the structure of an electronic device provided by an embodiment of the present application Figure 1 ;

[0070] Figure 4 Schematic diagram of the structure of a middle frame provided in an embodiment of the present application Figure 1 ;

[0071] Figure 5 Schematic diagram of the structure of a middle frame provided in an embodiment of the present application Figure 2 ;

[0072] Figure 6 Schematic diagram of the structure of a middle frame provided in an embodiment of the present application Figure 3 ;

[0073] Figure 7 Schematic diagram of the structure of an electronic device provided in an embodiment of the present application Figure 2 ;

[0074] Figure 8 Schematic diagram of the structure of a middle frame provided in an embodiment of the present application Figure 4 ;

[0075] Figure 9 Schematic diagram of the structure of a middle frame provided in an embodiment of the present application Figure 5 ;

[0076] Figure 10 Schematic diagram of the structure of a composite material provided in an embodiment of the present application;

[0077] Figure 11 Schematic diagram of the structure of a housing provided in an embodiment of the present application;

[0078] Figure 12 Schematic diagram of the structure of the first surface and the second surface of a protrusion provided in an embodiment of the present application;

[0079] Figure 13 Schematic diagram of the structure of a protrusion provided in an embodiment of the present application Figure 1 ;

[0080] Figure 14 Schematic diagram of the structure of a protrusion provided in an embodiment of the present application Figure 2 ;

[0081] Figure 15 Schematic diagram of the structure of a protrusion provided in an embodiment of the present application Figure 3 ;

[0082] Figure 16 This is a schematic structural diagram of the second filler provided in the embodiments of the present application;

[0083] Figure 17 This is a schematic flow chart of the preparation method of the composite material in the embodiments of the present application Figure 1 ;

[0084] Figure 18 This is a schematic flow chart of the preparation method of the composite material in the embodiments of the present application Figure 2 。 Detailed implementation manners

[0085] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application. Among them, in the description of the present application, unless otherwise specified, " / " means that the objects associated before and after are in an "or" relationship. For example, A / B may represent A or B; "and / or" in the present application is only a description of the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. These three situations, where A and B may be singular or plural. And, in the description of the present application, unless otherwise specified, "a plurality of" means two or more than two. "At least one (piece)" or its similar expression below refers to any combination of these items, including any combination of single item (piece) or plural items (pieces). For example, at least one (piece) of a, b, or c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, c may be single or multiple. In addition, in order to clearly describe the technical solutions in the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects.

[0086] Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and "first" and "second" do not necessarily mean different. At the same time, in some embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or more advantageous than other embodiments or design solutions. Exactly speaking, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific way for easy understanding.

[0087] For ease of understanding, some descriptions of concepts related to the embodiments of the present application are given as examples for reference. As follows:

[0088] A metal matrix composite (MMC) is a composite material with a metal or alloy as the matrix and fibers, whiskers, particles, etc. as the reinforcement.

[0089] Metal matrix composites not only retain the properties of the metal itself but also possess the comprehensive properties of composite materials. Through the optimized combination of different matrices and reinforcements, various high-performance composite materials are obtained, which have various special properties and excellent comprehensive properties. Metal matrix composites can be classified according to the type of matrix material, including aluminum-based, magnesium-based, zinc-based, copper-based, intermetallic compound-based composites, etc.

[0090] D50: The particle size corresponding to when the cumulative particle size distribution percentage of the sample reaches 50%.

[0091] In the related art, see Figure 1 , the frame 11 of the middle frame 10 is made of stainless steel or titanium alloy, and the middle plate 12 is made of aluminum alloy. Or the frame 11 of the middle frame 10 is made of aluminum alloy, and the middle plate 12 is made of aluminum alloy doped with silicon carbide (SiC) particles. The frame 11 and the middle plate 12 are connected by welding or riveting. On the one hand, the frame and the middle plate need to be processed separately in advance and then connected by external force or thermal connection. The bonding state between them is mechanical bonding, and the connection reliability is low, affecting the overall stiffness of the middle frame. For folding mobile phones, it will squeeze the display screen and the folding axis, increasing the failure ratio between the display screen and the folding axis. On the other hand, the elastic modulus of aluminum alloy is low, and the content of silicon carbide doped in the aluminum alloy doped with silicon carbide particles is small, and its elastic modulus is also low. Thus, the frame 11 and the middle plate 12 are prone to bending, causing the entire mobile phone to bend and deform in a three-point bending scenario as Figure 2 shown. In addition, the low elastic modulus of the middle plate 12 results in that the battery area in the middle plate 12 cannot be thinned and contribute more battery capacity. Furthermore, the user experience is reduced.

[0092] To solve the above technical problems, see Figure 3 , an embodiment of the present application provides an electronic device 300, which includes a display screen 31, a middle frame 32, a printed circuit board (PCB) 33, a battery 34, and a rear cover 35.

[0093] Among them, the display screen 31 and the rear cover 35 are installed on opposite sides of the middle frame 32. The inside of the middle frame 32 is the internal space of the electronic device 300, and the internal space can accommodate the PCB board 33 and the battery 34 of the electronic device 300. In some examples, the internal space can also accommodate internal components such as the SIM card, memory card, speaker, and receiver of the electronic device 300.

[0094] It should be noted that in other embodiments, the electronic device 300 may also not include the display screen 31, but include components such as a top cover that do not have a display function.

[0095] The electronic device may include, but is not limited to, devices such as mobile phones, tablet computers, laptop computers, ultra-mobile personal computers (UMPCs), netbooks, personal digital assistants (PDAs), wearable devices, artificial intelligence (AI) devices, etc.

[0096] The embodiments of the present application also provide a middle frame. Refer to Figure 4 , the middle frame 32 may include a middle plate 36 and a frame 37. The middle plate 36 is connected to the frame 37. The middle plate 36 is configured to be disposed inside the electronic device. The middle plate 36 is located inside the frame 37 and integrally formed with the frame 37. Among them, the middle plate 36 is used to carry the display screen and internal components of the electronic device, and provide a supporting force for the internal components, which can not only prevent the display screen from collapsing, but also protect the internal components.

[0097] In some examples, Figure 5 is Figure 3 the schematic structural diagram of the middle frame 32 cut along the A-A direction in an implementation manner. Refer to Figure 5 , the middle frame 32 includes an edge part 321, a central part 322 and a connecting part 323. The edge part 321, the central part 322 and the connecting part 323 are integrally formed. Specifically, the central part 322 is located inside the edge part 321, and the connecting part 323 is connected between the edge part 321 and the central part 322. Among them, the edge part 321 and the connecting part 323 form the frame 37, and the central part 322 forms the middle plate 36.

[0098] It should be noted that the integral formation of the edge part 321, the central part 322 and the connecting part 323 means that the edge part 321, the central part 322 and the connecting part 323 are jointly formed by a processing technology, rather than assembled and formed by processes such as riveting or welding after being processed separately.

[0099] In some embodiments, the edge part 321 forms the frame 37, and the central part 322 and the connecting part 323 form the middle plate 36. The above Figure 5 is only an example of the middle frame, and the embodiments of the present application do not limit the specific structure of the middle frame.

[0100] In some embodiments of the present application, refer to Figure 6, the middle plate 36 includes a battery area 361 and a non-battery area 362. The battery area 361 is used to carry the battery, and the non-battery area 362 is used to carry internal components such as the SIM card, memory card, speaker, and receiver of the electronic device.

[0101] The electronic device 300 provided by the embodiments of the present application is not limited to the above Figure 3 structure. In the electronic device 300, the rear cover may not be independently provided, and the rear cover may be provided in the middle frame. Refer to Figure 7 , the electronic device 300 may include a display screen 31, a PCB board 33, a battery 34, and a middle frame 32. The display screen 31 and the middle frame 32 are installed on opposite sides of the electronic device 300.

[0102] Among them, the middle frame 32 includes a frame 37 and a rear cover 38. The frame 37 is integrally connected to the rear cover 38, and the rear cover 38 is configured to be located on the back of the mobile phone. The internal space of the middle frame 32 can accommodate the PCB board 33 and the battery 34 of the electronic device 300. Similarly, the internal space can also accommodate internal components such as the SIM card, memory card, speaker, and receiver of the electronic device 300.

[0103] In some embodiments of the present application, refer to Figure 8 , the rear cover 38 includes a battery area 361 and a non-battery area 362. Similarly, the battery area 361 is used to carry the battery, and the non-battery area 362 is used to carry internal components such as the SIM card, memory card, speaker, and receiver of the electronic device.

[0104] In one implementation, refer to Figure 9 , a decorative layer 67 of the middle frame 32 may be formed on the surface of the rear cover 38 facing away from the display screen. Specifically, the decorative layer 67 may be provided on the outer surface of the entire rear cover 38, and the decorative layer 67 may also be provided on the outer surface of a part of the rear cover 38. The decorative layer 67 may be made of decorative anodized aluminum alloy. Since the aluminum alloy with low alloy content in the decorative anodized aluminum alloy has excellent decorative effects, the outer surface of the rear cover 38 has excellent decorative effects. Thus, it is ensured that the middle frame 32 has an excellent appearance. It should be noted that the appearance effect of the decorative anodized aluminum alloy means that the oxide film formed after the anodization of the aluminum alloy will not become dull or numb, and will not be easily corroded by hand sweat, etc. In this way, the decorative layer 67 not only has good decorative effects, but also is not easily damaged, has good integrity, can prevent the metal materials inside the middle frame 32 from being oxidized, and realizes effective protection of the metal materials inside the middle frame 32.

[0105] It should be noted that the above structures of the electronic device and the middle frame are only for illustrative purposes, and the embodiments of the present application do not specifically limit the corresponding structures of the electronic device and the middle frame.

[0106] The embodiments of the present application also provide a composite material, which can be used to prepare the middle frame in the above embodiments. Refer to Figure 10 , the composite material includes: a housing 90 and a first filler 91. Among them, the structure of the housing 90 can be a hollow columnar structure, for example, a hollow cylindrical structure and a hollow prismatic structure. The housing 90 encloses a first accommodation channel 92, and the structure of the first accommodation channel 92 can also be a columnar structure, for example, a cylindrical structure and a prismatic structure. The housing 90 can include at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, that is, it can be made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel.

[0107] In addition, the structure of the first filler 91 can also be a columnar structure, for example, a hollow cylindrical structure and a hollow prismatic structure. The first filler 91 can be disposed in the first accommodation channel 92 and combined with the inner wall of the first accommodation channel 92, and the combination includes metallurgical bonding. In this way, after the first filler 91 and the housing 90 form metallurgical bonding, the composite material can have good process performance, improve the connection reliability between the first filler 91 and the housing 90, and the overall rigidity of the composite material.

[0108] In some embodiments, the first filler 91 includes a first aluminum-based material, or a decorative anodized aluminum alloy, or a hard aluminum alloy, that is, it can be made of a first aluminum-based material, or a decorative anodized aluminum alloy, or a hard aluminum alloy.

[0109] In some embodiments of the present application, the first aluminum-based composite material can include pure aluminum or aluminum alloy, and at least one of the following: silicon carbide, aluminum oxide, boron carbide, titanium diboride, graphene, carbon nanotube, graphite, and diamond.

[0110] In some embodiments of the present application, the mass percentage of silicon carbide in the first aluminum-based composite material is less than 65%.

[0111] Among them, the silicon carbide includes submicron-sized first silicon carbide particles and micron-sized first silicon carbide particles. The mass percentage of the submicron-sized first silicon carbide particles in the first aluminum-based composite material is 0-20%, and the mass percentage of the micron-sized first silicon carbide particles in the first aluminum-based composite material is 5%-40%.

[0112] In an implementable manner, the mass percentage of the submicron-sized first silicon carbide particles in the first aluminum-based composite material is 0-10%, and the mass percentage of the micron-sized first silicon carbide particles in the first aluminum-based composite material is 5%-25%.

[0113] Among them, in the cumulative particle size distribution of the sub-micron first silicon carbide particles, D50 is 0.3 μm - 1.0 μm; in the cumulative particle size distribution of the micron-sized silicon carbide particles, D50 is 3 μm - 20 μm; and in the cumulative particle size distribution of the aluminum alloy in the first aluminum matrix composite, D50 is less than or equal to 20 μm.

[0114] In some other embodiments of the present application, the mass percentage of the sub-micron first silicon carbide particles in the first aluminum matrix composite may also be 0 - 10%, and the mass percentage of the micron-sized first silicon carbide particles in the first aluminum matrix composite may also be 8% - 25%. In the cumulative particle size distribution of the sub-micron first silicon carbide particles, D50 is 0.5 μm - 1.0 μm, and in the cumulative particle size distribution of the micron-sized silicon carbide particles, D50 is 3 μm - 20 μm.

[0115] In this way, the material of the first filler can be made of the first aluminum matrix composite. By controlling the content of the sub-micron first silicon carbide particles and the micron-sized first silicon carbide particles in the first aluminum matrix composite, the content of silicon carbide added to the aluminum alloy can be made more appropriate, thereby improving the elastic modulus and anti-bending ability of the first aluminum matrix composite.

[0116] In addition, the material of the first filler can also be made of decorative anodized aluminum alloy or hard aluminum alloy. Among them, the decorative aluminum alloy can be applied to the aluminum alloy system of the electronic device housing, including alloy systems such as 5-series aluminum alloy, 6-series aluminum alloy, and 7-series aluminum alloy with an aluminum content greater than 88%. The Vickers hardness of the hard aluminum alloy is greater than 150 HV. The decorative anodized aluminum alloy has a relatively high elastic modulus, and the hard aluminum alloy has a relatively high strength, which can improve the elastic modulus and anti-bending ability of the first filler.

[0117] In some embodiments, the above-mentioned housing 90 and the first filler 91 are also connected by mutually engaging protrusions and grooves.

[0118] It should be noted that the present application embodiments do not limit the specific setting positions of the protrusions and grooves. For example, protrusions can be provided on the inner wall of the housing 90, and grooves can be provided on the outer wall of the first filler 91. For another example, grooves can be provided on the inner wall of the housing 90, and protrusions can be provided on the outer wall of the first filler 91.

[0119] Based on the above, on the one hand, after the composite material obtained by combining the above-mentioned first filler and the housing is used to prepare the middle frame, the anti-bending ability, the overall drop anti-deformation ability and the strength of the entire middle frame can be improved.

[0120] On the other hand, the first filling body and the outer shell can be connected by mutually engaging protrusions and grooves, and the combination method of the two can be partial metallurgical bonding and partial mechanical bonding. Of course, the first filling body and the outer shell can also be fully metallurgically bonded. In this way, the bonding force between the two can be increased, so that the composite material has higher strength. Furthermore, after using this composite material to prepare the middle frame, the connection reliability is higher, and the frame and the middle plate / rear cover of the middle frame are integrally formed structures, improving the overall rigidity of the middle frame.

[0121] At the same time, the thickness of the middle plate in the middle frame provided by this application can reach 0.15 mm, which can thin the battery area where the battery is arranged in the middle frame and can accommodate a larger-capacity battery. Thus, more battery capacity can be contributed. Furthermore, the user experience can be improved.

[0122] It should be noted that the above composite material includes but is not limited to being used to prepare the middle frame, and can also be used to prepare other devices in the electronic device. This application does not specifically limit this.

[0123] In some embodiments of this application, the elastic modulus of the first filling body is greater than or equal to 85 GPa, and the elongation rate of the first filling body is greater than 3%.

[0124] In this way, the first filling body provided by the embodiments of this application has a high elastic modulus, which can improve the overall rigidity of the composite material and the rigidity of the prepared middle frame. In addition, the first filling body has a high elongation rate, that is, it has a strong plastic deformation ability. It can improve the processing diversity of the composite material and the processing diversity of the prepared middle frame.

[0125] In some embodiments of this application, refer to Figure 11 , the protrusion 101 can be arranged on the inner wall of the first accommodating channel 92. Continuing to refer to Figure 10 , the groove 102 can be arranged on the outer wall of the first filling body 91, and the protrusion 101 and the groove 102 are in interference fit.

[0126] In an implementable manner, the groove 102 can also be arranged on the inner wall of the first accommodating channel 92, the protrusion 101 can also be arranged on the outer wall of the first filling body 91, and the protrusion 101 and the groove 102 are in interference fit.

[0127] In this way, the protrusion 101 on the inner wall of the first accommodating channel 92 and the groove 102 on the outer wall of the first filling body 91 can be combined by extrusion. The combination method of the two can be partial metallurgical bonding and partial mechanical bonding, which can generate a large bonding force between the outer shell 90 and the first filling body 91, and the two can be tightly combined. Thus, the strength of the composite material is improved.

[0128] In some embodiments of this application, refer toFigure 12 , the protrusion 101 includes a first surface 1011 and a second surface 1012 which are oppositely arranged. Both the first surface 1011 and the second surface 1012 are arranged parallel to the center line of the first accommodation channel 92. One end of the first surface 1011 and the second surface 1012 is connected to the inner wall of the housing 90, and the other ends of the first surface 1011 and the second surface 1012 intersect or are parallel.

[0129] In some examples, the structure of the protrusion 101 can be an angular structure. Continue to refer to Figure 12 , the structure of the protrusion 101 can be a toothed structure, and one end of the first surface 1011 and the second surface 1012 of the protrusion 101 intersects.

[0130] In some examples, the structure of the protrusion 101 can be an arc structure or an angular structure. The protrusion 101 can also include a third surface 1013, and the third surface 1013 intersects with the first surface 1011 and the second surface 1012.

[0131] Exemplarily, the structure of the protrusion 101 can be a prismatic structure. Refer to Figure 13 , the third surface 1013 of the protrusion 101 intersects with one end of the first surface 1011 and the second surface 1012 and forms an angle.

[0132] Refer to Figure 14 , one end of the first surface 1011 and the second surface 1012 of the protrusion 101 is parallel, and the third surface 1013 forms an angle with the first surface 1011 and the second surface 1012.

[0133] Refer to Figure 15 , one end of the first surface 1011 and the second surface 1012 of the protrusion 101 is parallel, and the third surface 1013 is an arc surface and forms an angle with the first surface 1011 and the second surface 1012.

[0134] The above-mentioned protrusion 101 can be tooth-shaped, columnar or other irregular special-shaped shapes, etc. The groove 102 can be a complementary structure corresponding to the protrusion 101, which will not be elaborated here. It should be noted that the embodiments of the present application do not specifically limit the implementation forms of the protrusion 101 and the groove 102.

[0135] In this way, by providing the protrusion 101 and including the first surface 1011 and the second surface 1012 in the protrusion 101 in the embodiments of the present application, the contact area between the housing 90 and the first filling body 91 can be increased, so that a greater bonding force is generated between the housing 90 and the first filling body 91, thereby improving the strength of the composite material.

[0136] In some embodiments of the present application, both the protrusion 101 and the groove 102 are multiple, and each protrusion 101 is fitted with a groove 102.

[0137] There may be multiple protrusions 101, which are provided on the inner wall of the outer shell 90, and each protrusion 101 is engaged with a groove 102. In addition, the multiple protrusions 101 may have the same structure or different structures. The multiple grooves 102 may have the same structure or different structures.

[0138] Thus, by providing multiple protrusions 101 and grooves 102, each protrusion 101 includes a first surface 1011 and a second surface 1012, the contact area between the outer shell 90 and the first filler 91 can be increased. At the same time, each protrusion 101 is engaged with a groove 102, which can generate a large bonding force between the outer shell 90 and the first filler 91, thereby improving the strength of the composite material.

[0139] In some embodiments of the present application, the multiple protrusions 101 may be uniformly provided on the inner wall of the outer shell 90. Exemplarily, the multiple protrusions 101 may be uniformly provided along the center line direction of the first accommodation channel 92, and / or along the direction perpendicular to the center line of the first accommodation channel 92.

[0140] Thus, by uniformly providing multiple protrusions 101 on the inner wall of the outer shell 90, the entire structure of the outer shell 90 can be made more stable, so as to ensure a large bonding force after subsequent engagement with the multiple grooves 102, and make the composite material have a high strength.

[0141] In some embodiments of the present application, see Figure 16 , the composite material further includes a second filler 93. A second accommodation channel 94 is provided in the first filler 91, and the center line of the second accommodation channel 94 is parallel to the center line of the first accommodation channel 92. Among them, the structure of the second accommodation channel 94 may be a columnar structure, for example, a cylindrical structure and a prismatic structure.

[0142] In addition, the structure of the second filler 93 may also be a columnar structure, for example, a hollow cylindrical structure and a hollow prismatic structure. The second filler 93 may be provided in the second accommodation channel 94 and combined with the first filler 91, and the combination includes metallurgical bonding.

[0143] In some embodiments of the present application, the second filler 93 may include a second aluminum-based material, that is, it is made of the second aluminum-based material. The second aluminum-based composite material includes pure aluminum or aluminum alloy, and at least one of the following: silicon carbide, aluminum oxide, boron carbide, titanium diboride, graphene, carbon nanotubes, graphite, and diamond.

[0144] In some embodiments of the present application, the mass percentage of silicon carbide in the second aluminum-based composite material is less than 65%.

[0145] Among them, the silicon carbide includes sub-micron-sized second silicon carbide particles and micron-sized second silicon carbide particles. The mass percentage of the sub-micron-sized second silicon carbide particles in the second aluminum matrix composite is 0-10%, and the mass percentage of the micron-sized second silicon carbide particles in the second aluminum matrix composite is 15%-50%.

[0146] Among them, in the cumulative particle size distribution of the sub-micron-sized second silicon carbide particles, D50 is 0.5 microns - 1.0 microns, in the cumulative particle size distribution of the micron-sized second silicon carbide particles, D50 is 3 microns - 20 microns, and in the cumulative particle size distribution of the aluminum alloy in the second aluminum matrix composite, D50 is less than or equal to 20 microns.

[0147] Thus, the material of the second filler can be made of the second aluminum matrix composite. By controlling the content of the sub-micron-sized second silicon carbide particles and the micron-sized second silicon carbide particles in the second aluminum matrix composite, the content of silicon carbide added to the aluminum alloy can be made more suitable, thereby enhancing the higher elastic modulus and anti-bending ability of the second aluminum matrix composite.

[0148] Based on the above, on the one hand, after using the composite material including the first filler, the second filler and the outer shell to prepare the middle frame, the anti-bending ability, the overall drop anti-deformation ability and the strength of the entire middle frame can be improved.

[0149] On the other hand, after the first filler and the second filler are fitted together, they can be connected to the outer shell through mutually engaging protrusions and grooves, and the combination method of the two is partial metallurgical bonding and partial mechanical bonding. Of course, the two can also be all metallurgical bonding. In this way, the bonding force between the two can be increased, so that the composite material has higher strength. Furthermore, after using this composite material to prepare the middle frame, the connection reliability is relatively high.

[0150] In some embodiments of the present application, the elastic modulus of the second filler is greater than or equal to 110 GPa, and the elongation rate of the second filler is greater than 0.2%. The second fillers all have relatively high elastic modulus, and the elastic modulus of the second filler is higher than that of the first filler. The composite material made of the first filler and the second filler also has relatively high elastic modulus, which can improve the overall rigidity of the composite material. At the same time, the second fillers all have relatively high elongation rate. In this way, the composite material made of the first filler and the second filler has strong plastic deformation ability and high processing diversity.

[0151] In some embodiments of the present application, the decorative anodized aluminum alloy includes 6013 aluminum alloy, 3003 aluminum alloy, 6061 aluminum alloy, 6063 aluminum alloy and 7003 aluminum alloy. Among them, the aluminum content in the decorative anodized aluminum alloy is greater than 90%.

[0152] In some embodiments of the present application, the aluminum alloys in the first aluminum matrix composite material and the second aluminum matrix composite material include 7055 aluminum alloy, 2024 aluminum alloy, 7034 aluminum alloy, 5052 aluminum alloy, and 5083 aluminum alloy.

[0153] The first aluminum matrix composite material and the second aluminum matrix composite material may include fiber-doped particles, and the fiber-doped particles include carbon fiber-doped particles. The diameter of the fiber-doped particles may be less than 200 nm.

[0154] The embodiments of the present application further provide a method for preparing a composite material for preparing the composite material in the above embodiments. Refer to Figure 17 , the method includes:

[0155] S1701. Prepare a housing, and the housing encloses a first accommodation channel.

[0156] In some embodiments of the present application, refer to Figure 18 , in the process of preparing the housing, a first rod 1801 may be provided first, and a first accommodation channel is formed in the first rod 1801, and the center line of the first accommodation channel is parallel to the center line of the first rod 1801. In addition, a protrusion 1803 may be formed on the inner wall of the first accommodation channel, and the protrusion 1803 extends in a direction parallel to the center line of the first rod.

[0157] In some embodiments, the housing may be made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel. Specifically, at least one of pure titanium, titanium alloy, stainless steel, and alloy steel may be melted and extruded into a hollow cylindrical rod. Among them, the titanium alloy may be TC4 titanium alloy, and the alloy steel may be 316L stainless steel. The cylindrical rod may be the first rod 1801, and the hollow structure in the cylindrical rod forms the first accommodation channel, and the center line of the hollow structure is parallel to the center line of the entire cylindrical rod. In addition, a protrusion may be provided on the inner wall of the hollow cylindrical rod, and the protrusion extends in a direction parallel to the center line of the entire cylindrical rod. It should be noted that the specific structure and implementation form of the protrusion are similar to those of the protrusion introduced in the above composite material, and will not be elaborated here.

[0158] S1702. Prepare a first filling body.

[0159] In some embodiments of the present application, continue to refer to Figure 18 , in the process of preparing the first filling body, a second rod 1802 may be provided, and a groove 1804 is formed on the outer wall of the second rod 1802, and the groove 1804 extends in a direction parallel to the center line of the second rod 1802.

[0160] In some embodiments, the second rod body 1802 can be made of a first aluminum matrix composite material, or a decorative anodized aluminum alloy, or a hard aluminum alloy. Specifically, the first aluminum matrix composite material, or the decorative anodized aluminum alloy, or the hard aluminum alloy can be made into a cylindrical rod body with a diameter of 20 mm - 500 mm by milling or turning, and this cylindrical rod body is the second rod body 1802. Additionally, a groove 1804 can be provided on the outer wall of the second rod body 1802, and the groove 1804 extends along a direction parallel to the center line of the second rod body 1802. It should be noted that the specific structure and implementation form of the groove are similar to those of the groove introduced in the above composite material, and will not be elaborated here.

[0161] In some embodiments of the present application, the preparation method of the first aluminum matrix composite material includes:

[0162] Pre-treat and surface-modify the sub-micron first silicon carbide particles and the micron first silicon carbide particles. Specifically, perform pre-treatments such as pickling, sensitization, and activation on the sub-micron first silicon carbide particles and the micron first silicon carbide particles, and perform surface modification treatments such as electroless copper plating or nickel plating.

[0163] Next, mix the treated sub-micron first silicon carbide particles and the micron first silicon carbide particles to obtain a first reinforcement material. Among them, the mass percentage content of the sub-micron first silicon carbide particles in the first aluminum matrix composite material can be 0 - 20%, and the mass percentage content of the micron first silicon carbide particles in the first aluminum matrix composite material can be 5% - 40%.

[0164] In an achievable manner, the mass percentage content of the sub-micron first silicon carbide particles in the first aluminum matrix composite material can be 0 - 10%, and the mass percentage content of the micron first silicon carbide particles in the first aluminum matrix composite material can be 5% - 25%.

[0165] In another achievable manner, the mass percentage content of the micron first silicon carbide particles in the first aluminum matrix composite material can also be 8% - 25%. The D50 in the cumulative particle size distribution of the sub-micron first silicon carbide particles is 0.3 microns - 1.0 microns, and the D50 in the cumulative particle size distribution of the micron silicon carbide particles is 3 microns - 20 microns.

[0166] Uniformly mix the aluminum alloy powder and the above first reinforcement powder in a ball mill to obtain the first aluminum matrix composite material. The first aluminum matrix composite material should achieve no segregation and no agglomeration.

[0167] The first aluminum matrix composite material is cold-pressed and formed under a hydraulic press to form a first cold-pressed blank. Among them, D50 in the cumulative particle size distribution of the aluminum alloy is less than or equal to 20 microns, the cold-pressing pressure is 3 MPa - 15 MPa, and the pressure holding time is 5 min - 45 min.

[0168] Then, the above-mentioned first cold-pressed blank is placed in a hot-pressing mold, and graphite paper with a thickness of 0.3 mm - 1 mm is used as a lubricating medium to facilitate demolding. It is hot-pressed and sintered in a hot-pressing furnace with a metal wire such as molybdenum wire as the resistance heating wire to obtain a first filler. Among them, the temperature is 580 °C - 620 °C, the pressure is 5 MPa - 30 MPa, and the heat preservation time is 10 min - 60 min.

[0169] S1703. Install the first filler in the first accommodation channel, and the first filler is combined with the inner wall of the first accommodation channel, and the combination includes metallurgical combination.

[0170] In some embodiments of the present application, during the process of installing the first filler in the first accommodation channel, the outer shell and the first filler can be extruded. The outer shell and the first filler are connected by mutually engaged protrusions and grooves so that the outer shell and the first filler are in interference fit.

[0171] Specifically, during the process of extruding the outer shell and the first filler, isostatic pressing treatment can be performed on the outer shell and the first filler. Exemplarily, the outer shell and the first filler can be extruded according to a predetermined extrusion ratio, and the outer shell and the first filler are heated while being extruded.

[0172] In some embodiments of the present application, during the process of installing the first filler in the first accommodation channel, the second rod 1802 can be inserted into the first accommodation channel along a direction parallel to the center line of the first rod 1801, and the protrusion 1803 is embedded in the groove 1804.

[0173] In some embodiments, the above-mentioned second rod 1802 can be placed in the first rod 1801 so that the first rod 1801 and the second rod 1802 are in interference fit.

[0174] Specifically, the first rod and the second rod can be placed together and combined by cold isostatic pressing or hot isostatic pressing so that the first rod and the second rod are combined. Exemplarily, cold isostatic pressing can be performed on the titanium alloy formed by pressing and the first aluminum matrix composite material formed by pressing to achieve the combination of the first rod and the second rod. Another example is that hot isostatic pressing can be performed on the titanium alloy formed by pressing and the decorative anodized aluminum alloy formed by pressing to achieve the combination of the first rod and the second rod.

[0175] In some embodiments, the first filler and the outer shell can be placed in an extruder, and a predetermined extrusion ratio is controlled to form a composite material with partial metallurgical bonding and partial mechanical bonding. Among them, the predetermined extrusion ratio is 5:20. It should be noted that the process of extruding the outer shell and the first filler can be hot extrusion, and of course, other extrusion methods can also be used, which are not specifically limited here.

[0176] In some embodiments of the present application, the extruded outer shell and the first filler can also be fabricated into a cuboid structure and subjected to solution treatment and aging treatment to obtain a composite material with a cuboid structure. Specifically, the extruded outer shell and the first filler are fabricated into a cuboid structure, solution-treated at 450°C - 480°C for 1h - 4h, then quenched with cold water, and then the quenched material is artificially aged at 120°C - 150°C for 2h - 18h. Among them, the length corresponding to the cuboid structure is 170mm - 200mm, and the width is 60mm - 85mm.

[0177] Based on the above content, by using at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, the composite material obtained by combining with the first aluminum-based composite material can also have a relatively high elastic modulus. In addition, at least one of pure titanium, titanium alloy, stainless steel, and alloy steel can be combined with the first aluminum-based composite material through mutually engaging protrusions and grooves, and the bonding method of the materials is partial metallurgical bonding and partial mechanical bonding, and the bonding force between the two is relatively large, so that the composite material has relatively high strength. Furthermore, after the composite material is used to prepare the middle frame, the overall rigidity and connection reliability of the middle frame are improved.

[0178] In some embodiments of the present application, in the above S1701, during the process of preparing the first filler, a second accommodation channel is further formed on the first filler, and the center line of the second accommodation channel is parallel to the center line of the first accommodation channel. Specifically, during the process of making the second rod, a hollow cylindrical structure can be provided in the second rod, that is, the hollow structure forms the second accommodation channel. The center line of the second accommodation channel is parallel to the center line of the first accommodation channel.

[0179] In addition, before extruding the outer shell and the first filler, it further includes: preparing a second filler, installing the second filler in the second accommodation channel, and making the second filler combine with the second accommodation channel, and the combination includes metallurgical bonding.

[0180] In some embodiments, continue to refer to Figure 18 , a third rod 1805 can be provided, and the third rod 1805 is made of a second aluminum-based composite material. Specifically, the second aluminum-based composite material can be made into a cylindrical rod by milling or turning, and this cylindrical rod is the third rod 1805.

[0181] Meanwhile, during the process of installing the second filling body into the second accommodating channel, the third rod 1805 can be placed into the hollow cylindrical structure of the second rod 1802 and combined with the second accommodating channel. The combination includes metallurgical bonding so that the third rod 1805 and the second rod 1802 form an interference fit. Specifically, the third rod 1805 and the second rod 1802 can be placed into an extruder, and a composite material can be formed according to a predetermined extrusion ratio. Among them, the predetermined extrusion ratio is 5:20.

[0182] In some embodiments of the present application, the preparation method of the second aluminum matrix composite material includes:

[0183] Perform pretreatment and surface modification on the submicron-sized second silicon carbide particles and micron-sized second silicon carbide particles. Specifically, perform pretreatment such as pickling, sensitization, and activation on the submicron-sized second silicon carbide particles and micron-sized second silicon carbide particles, and perform surface modification such as electroless copper plating or nickel plating.

[0184] Then, mix the treated submicron-sized second silicon carbide particles and micron-sized second silicon carbide particles to obtain the second reinforcing material. Among them, the mass percentage content of the submicron-sized second silicon carbide particles in the second aluminum matrix composite material is 0-10%, and the mass percentage content of the micron-sized second silicon carbide particles in the second aluminum matrix composite material is 15%-50%.

[0185] Uniformly mix the aluminum alloy powder and the above-mentioned second reinforcing powder in a ball mill to obtain the second aluminum matrix composite material. The second aluminum matrix composite material should achieve no segregation and no agglomeration.

[0186] In some embodiments of the present application, cold press the second aluminum matrix composite material under a hydraulic press to form a second cold-pressed blank. Among them, the cold press pressure is 3 MPa - 15 MPa, and the pressure holding time is 5 min - 45 min.

[0187] Then, place the above-mentioned second cold-pressed blank in a hot press molding die, and use graphite paper with a thickness of 0.3 mm - 1 mm as a lubricating medium to facilitate demolding. Perform hot press sintering molding in a hot press furnace with a metal wire such as molybdenum wire as a resistance heating wire to obtain the second filling body. Among them, the temperature is 580 °C - 620 °C, the pressure is 5 MPa - 30 MPa, and the heat preservation time is 10 min - 60 min.

[0188] Thus, the titanium alloy, alloy steel, first aluminum matrix composite, and second aluminum matrix composite have relatively high elastic moduli, so that the resulting composite material can also have a relatively high elastic modulus. In addition, the first aluminum matrix composite to which the second aluminum matrix composite is adhered can be combined with at least one of pure titanium, titanium alloy, stainless steel, and alloy steel through mutually engaging protrusions and grooves. The bonding method of the materials is partial metallurgical bonding and partial mechanical bonding, and the bonding force between the two is relatively large, making the composite material have relatively high strength. Furthermore, after the composite material is used to prepare the middle frame, the overall rigidity and connection reliability of the middle frame are improved.

[0189] The embodiment of the present application further provides a method for preparing a middle frame. The middle frame is made of the above composite material. The frame of the middle frame includes a housing, and the middle plate includes a first filling body. The specific method for preparing the middle frame may include: cutting the composite material along a square perpendicular to the center line of the first accommodation channel to form a plate body. Then, machining the plate body so that the housing forms the frame of the middle frame, and the first filling body forms the middle plate of the middle frame.

[0190] In some embodiments of the present application, the height of the middle plate is 0.15 mm.

[0191] Exemplarily, the obtained cuboid composite material can be cut into a blank with a height of 7 mm - 15 mm to form a plate body. Then, the plate body is processed by computer numerical control (CNC) machining to form the middle frame. The frame part of the middle frame includes a housing, and the middle plate part includes a first filling body.

[0192] In the embodiment of the present application, the frame part of the middle frame is made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the middle plate part is made of the first aluminum matrix composite, or a decorative anodized aluminum alloy, or a hard aluminum alloy. On the one hand, the first aluminum matrix composite, the decorative anodized aluminum alloy, or the hard aluminum alloy has relatively high elastic modulus and relatively high hardness, which improves the anti-bending ability of the entire middle plate and the anti-deformation ability against overall dropping, thereby improving the strength of the entire middle frame. On the other hand, the corresponding thickness of the middle plate can be 0.15 mm, which thins the battery area where the battery is arranged in the middle frame, enabling a larger-capacity battery to be placed, and thus contributing more battery capacity. On the other hand, the frame and the middle plate in the middle frame are integrally formed, with relatively high connection reliability, improving the overall stiffness of the middle frame.

[0193] In some embodiments of the present application, the elastic modulus of the second filling body is greater than the elastic modulus of the first filling body. Referring further to Figure 6, the battery area 361 in the middle plate can be made of the second filler, and the non-battery area 362 can be made of the first filler. This can significantly improve the anti-bending ability of the battery area in the middle plate and the anti-deformation ability against overall dropping, thereby improving the reliability of protecting the battery.

[0194] The embodiment of the present application also provides a method for manufacturing a middle frame. The middle frame is made of the above composite material. The middle frame includes a frame and a rear cover. The frame is connected to the rear cover, and the rear cover is configured to be located on the back of the mobile phone. The frame includes a housing, and the rear cover includes a first filler. At least part of the outer surface of the rear cover is provided with a decorative layer, and the decorative layer is made of decorative anodized aluminum alloy.

[0195] The specific method for manufacturing the middle frame may include: cutting the composite material along a square perpendicular to the center line of the above first accommodation channel to form a plate body. Then, the plate body is machined so that the housing forms the frame of the middle frame, and the first filler forms the rear cover of the middle frame. During the process of forming the rear cover, anodization can also be performed on at least part of the outer surface of the rear cover to obtain a decorative layer. The decorative layer includes decorative anodized aluminum alloy.

[0196] In some embodiments of the present application, the height of the rear cover is 0.6 mm.

[0197] Exemplarily, the obtained cuboid composite material can be cut into a blank with a height of 7 mm - 15 mm to form a plate body. Then, the plate body is processed by CNC to form the middle frame. The frame part of the middle frame includes a housing, and the rear cover part includes a first filler.

[0198] In the embodiment of the present application, the frame part of the middle frame is made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the rear cover part is made of the first aluminum-based composite material, or decorative anodized aluminum alloy, or hard aluminum alloy. On the one hand, the first aluminum-based composite material, decorative anodized aluminum alloy, or hard aluminum alloy has a relatively high elastic modulus and relatively high hardness, which can improve the anti-bending ability of the entire middle plate and the anti-deformation ability against overall dropping, thereby improving the strength of the entire middle frame. On the other hand, the corresponding thickness of the rear cover can be 0.6 mm, reducing the battery area in the middle frame where the battery is placed, enabling a larger-capacity battery to be placed, and thus contributing more battery capacity. On the other hand, the frame and the rear cover in the middle frame are integrally formed, with relatively high connection reliability and improved overall stiffness of the middle frame.

[0199] In some embodiments of the present application, continue to refer to Figure 8, the battery area 361 in the rear cover includes a second filler, and the non-battery area 362 includes a first filler. By using the second filler to make the battery area in the rear cover, the anti-bending ability of the battery area and the anti-deformation ability against overall dropping can be significantly improved. Thereby, the reliability of protecting the battery can be enhanced. At the same time, a decorative layer made of decorative anodized aluminum alloy is provided on at least part of the outer surface of the rear cover to enhance the appearance effect of the middle frame. Furthermore, the user experience is improved.

[0200] The above composite materials and the middle frames prepared based on the composite materials are introduced below through specific embodiments, and the middle frames are prepared with the composite materials prepared in the embodiments to test the performance of the middle frames.

[0201] In some embodiments of the present application, the steps of preparing the first filler and the second filler are as follows:

[0202] The sub-micron first silicon carbide particles and the micron first silicon carbide particles are pre-treated and surface-modified. Then, the treated sub-micron first silicon carbide particles and the micron first silicon carbide particles are mixed to obtain a first reinforcement material. Among them, the mass percentage of the sub-micron first silicon carbide particles in the first aluminum matrix composite material can be 2%, and the mass percentage of the micron first silicon carbide particles in the first aluminum matrix composite material can be 18%.

[0203] The 7055 aluminum alloy powder and the above first reinforcement powder are uniformly mixed in a ball mill to obtain a first aluminum matrix composite material.

[0204] The sub-micron second silicon carbide particles and the micron second silicon carbide particles are pre-treated and surface-modified. Then, the treated sub-micron second silicon carbide particles and the micron second silicon carbide particles are mixed to obtain a second reinforcement material. Among them, the mass percentage of the sub-micron second silicon carbide particles in the second aluminum matrix composite material is 5%, and the mass percentage of the micron second silicon carbide particles in the second aluminum matrix composite material is 40%.

[0205] The 7055 aluminum alloy powder and the above second reinforcement powder are uniformly mixed in a ball mill to obtain a second aluminum matrix composite material.

[0206] The first aluminum matrix composite material and the second aluminum matrix composite material are respectively cold-pressed and formed under a hydraulic press to form cold-pressed blanks. Among them, the cold-pressing pressure is 10 MPa, and the pressure-holding time is 30 min.

[0207] Subsequently, the above two cold-pressed green compacts are respectively placed in a hot-pressing mold, and a graphite paper with a thickness of 0.6 mm is used as a lubricating medium to facilitate demolding. Hot-pressing sintering is carried out in a hot-pressing furnace with a metal wire such as molybdenum wire as the resistance heating wire to obtain the first filling body and the second filling body. Among them, the temperature is 590 °C, the pressure is 25 MPa, and the heat preservation time is 40 min.

[0208] The steps for preparing the composite material are as follows:

[0209] The first filling body is provided with a hollow cylindrical structure, and the first filling body encloses a second accommodating channel.

[0210] The second filling body is installed in the second accommodating channel, and the diameter of the second filling body is 300 mm. Specifically, the second filling body is placed inside the first filling body and put into an extruder, and according to a predetermined extrusion ratio, the first filling body and the second filling body are combined. Among them, the diameter of the combined first filling body and second filling body is 350 mm.

[0211] Use at least one of pure titanium, titanium alloy, stainless steel, and alloy steel to prepare the outer shell, and the outer shell encloses a first accommodating channel.

[0212] The first filling body and the second filling body are installed in the first accommodating channel, and the outer shell and the first filling body are connected through mutually engaged protrusions and grooves.

[0213] Extrude the outer shell and the first filling body according to a predetermined extrusion ratio to obtain a cuboid-shaped composite material. The length of the cuboid-shaped composite material is 175 mm, and the width is 74 mm.

[0214] The cuboid-shaped composite material is solution-treated at 450 °C for 2 h, then quenched with cold water, and then the quenched material is artificially aged at 140 °C for 16 h to obtain the composite material for preparing the middle frame.

[0215] The steps for preparing the middle frame are as follows:

[0216] The above-obtained composite material is cut into a blank with a height of 10 mm to form a plate body. Then, the plate body is subjected to CNC machining to form the middle frame. The border part of the middle frame is made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the middle plate part is made of the first aluminum matrix composite material.

[0217] Among them, the middle plate part may include a battery area and a non-battery area. The battery area is made of the second aluminum matrix composite material, and the non-battery part is made of the first aluminum matrix composite material.

[0218] Alternatively, the frame portion of the middle frame is made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the back cover portion is made of a first aluminum matrix composite material.

[0219] Among them, the back cover portion may include a battery area and a non-battery area. The battery area is made of a second aluminum matrix composite material, and the non-battery portion is made of a first aluminum matrix composite material.

[0220] As described above, the elastic modulus of the first aluminum matrix composite material is 101 GPa, and the elongation is 6.1%. The elastic modulus of the second aluminum matrix composite material is 145 GPa, and the elongation is 1.7%.

[0221] In some other embodiments of the present application, the steps for preparing the first filler are as follows:

[0222] Perform pretreatment and surface modification on sub-micron first silicon carbide particles and micron-sized first silicon carbide particles. Then, mix the treated sub-micron first silicon carbide particles and micron-sized first silicon carbide particles to obtain a first reinforcement material. Among them, the mass percentage of the sub-micron first silicon carbide particles in the first aluminum matrix composite material can be 5%, and the mass percentage of the micron-sized first silicon carbide particles in the first aluminum matrix composite material can be 21%.

[0223] Uniformly mix 7034 aluminum alloy powder with the above-mentioned first reinforcement powder in a ball mill to obtain a first aluminum matrix composite material.

[0224] Cold press the first aluminum matrix composite material under a hydraulic press to form a cold-pressed blank. Among them, the cold press pressure is 9 MPa, and the pressure holding time is 40 min.

[0225] Then, place the above cold-pressed blank in a hot press mold, and use a graphite paper with a thickness of 0.5 mm as a lubricating medium to facilitate demolding. Perform hot press sintering in a hot press furnace with a metal wire such as molybdenum wire as a resistance heating wire to obtain a first filler. Among them, the temperature is 580 °C, the pressure is 30 MPa, and the heat preservation time is 60 min.

[0226] The steps for preparing the composite material are as follows:

[0227] Prepare a housing using at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the housing encloses a first accommodation channel.

[0228] Install the first filler (with a diameter of 400 mm) in the first accommodation channel, and connect the housing and the first filler through mutually engaged protrusions and grooves.

[0229] Extrude the outer shell and the first filler body according to a predetermined extrusion ratio to obtain a composite material with a cuboid structure. The length of the composite material with a cuboid structure is 190 mm, and the width is 80 mm.

[0230] Subject the composite material with a cuboid structure to solution treatment at 450 °C for 4 h, then quench it with cold water, and then perform artificial aging treatment on the quenched material at 150 °C for 15 h to obtain a composite material for preparing the middle frame.

[0231] The steps for preparing the middle frame are as follows:

[0232] Cut the above-obtained composite material into blanks with a height of 10 mm to form a plate body. Then, perform CNC machining on the plate body to form the middle frame. The border part of the middle frame is made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the middle plate part is made of the first aluminum-based composite material.

[0233] Alternatively, the border part of the middle frame is made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the back cover part is made of the first aluminum-based composite material.

[0234] Above, the elastic modulus of the first aluminum-based composite material is 102 GPa, and the elongation is 5.5%.

[0235] In some embodiments of the present application, the steps for preparing the composite material are as follows:

[0236] Prepare the first filler body using a decorative anodized aluminum alloy.

[0237] Prepare the outer shell using at least one of pure titanium, titanium alloy, stainless steel, and alloy steel. The outer shell encloses a first accommodation channel. Among them, the titanium alloy can be TC4 titanium alloy, the alloy steel can be 316L alloy steel, and the decorative anodized aluminum alloy can be 6013 anodized aluminum alloy.

[0238] Install the first filler body in the first accommodation channel, and connect the outer shell and the first filler body through mutually engaged protrusions and grooves.

[0239] Extrude the outer shell and the first filler body according to a predetermined extrusion ratio to obtain a composite material with a cuboid structure.

[0240] The steps for preparing the middle frame are as follows:

[0241] Cut the above-obtained composite material into blanks with a height of 10 mm to form a plate body. Then, perform CNC machining on the plate body to form the middle frame. The border part of the middle frame is made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the middle plate part is made of a decorative anodized aluminum alloy.

[0242] Alternatively, the frame part of the middle frame is made of at least one of pure titanium, titanium alloy, stainless steel, and alloy steel, and the back cover part is made of decorative anodized aluminum alloy.

[0243] It should be noted that a decorative layer made of decorative anodized aluminum alloy can be provided on the outer surface of at least part of the back cover in the above middle frame, which will not be elaborated here.

[0244] Based on the above embodiments, the elastic modulus of the first aluminum matrix composite provided by this application is greater than or equal to 85 GPa, and the elastic modulus of the second aluminum matrix composite is greater than or equal to 110 GPa. On the one hand, the high-modulus first aluminum matrix composite, or the first and second aluminum matrix composites, can be applied to the entire middle plate or back cover to increase the elastic modulus of the entire middle frame, thereby improving the thermal conductivity and rigidity of the entire middle frame. On the other hand, the battery area in this application can use the high-modulus second aluminum matrix composite to improve the reliability of protecting the battery. In addition, the thickness of the middle plate or back cover can be reduced to 0.15 mm, which can increase the battery capacity to a certain extent. On the other hand, the middle plate or back cover and the frame are connected by mutually engaged protrusions and grooves, which is cost-saving and has high connection reliability. At the same time, a decorative layer can also be provided in part of the back cover area, which has higher ornamental value. Furthermore, the user experience is improved.

[0245] An embodiment of this application provides a middle frame, which is made of the above composite material. The middle frame includes a frame and a middle plate. The middle plate is connected to the frame and is configured to be disposed inside the electronic device; the frame includes a housing, and the middle plate includes a first filler.

[0246] Specifically, the middle plate includes a battery area and a non-battery area. The battery area includes a second filler, and the non-battery area includes a first filler.

[0247] An embodiment of this application provides a middle frame, which is made of the above-mentioned composite material. The middle frame includes a frame and a back cover. The frame is connected to the back cover, and the back cover is configured to be located on the back of the electronic device; the frame includes a housing, and the back cover includes a first filler.

[0248] Specifically, the back cover includes a battery area and a non-battery area. The battery area includes a second filler, and the non-battery area includes a first filler. A decorative layer is provided on the outer surface of at least part of the back cover, and the decorative layer is made of decorative anodized aluminum alloy.

[0249] An embodiment of this application provides an electronic device, which includes a display screen, a battery, and the middle frame as described above. The display screen and the battery are disposed on the middle frame.

[0250] The embodiments of the present application described above do not constitute a limitation to the protection scope of the present application.

[0251] In some solutions, multiple embodiments of the present application can be combined and the combined solution can be implemented. Optionally, some operations in the processes of the method embodiments are optionally combined, and / or the order of some operations is optionally changed. Moreover, the execution order between the steps of each process is only exemplary and does not constitute a limitation to the execution order between the steps. There can also be other execution orders between the steps. It is not intended to indicate that the execution order is the only order in which these operations can be executed.

[0252] Those of ordinary skill in the art will think of various ways to reorder the operations described in the embodiments of the present application. In addition, it should be noted that the process details involved in a certain embodiment of the present application are also applicable to other embodiments in a similar manner, or different embodiments can be used in combination.

[0253] In addition, some steps in the method embodiments can be equivalently replaced with other possible steps. Or, some steps in the method embodiments can be optional and can be deleted in some usage scenarios. Or, other possible steps can be added to the method embodiments.

[0254] Moreover, the method embodiments can be implemented separately or in combination.

[0255] The above content is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any change or replacement within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A composite material, characterized in that, it comprises: a housing that encloses a first accommodation channel; a first filler; the first filler is disposed in the first accommodation channel, and the first filler is combined with the inner wall of the first accommodation channel, and the combination includes metallurgical bonding.

2. The composite material according to claim 1, characterized in that, the housing and the first filler are further connected by mutually engaging protrusions and grooves.

3. The composite material according to claim 2, characterized in that, the protrusions are disposed on the inner wall of the first accommodation channel, and the grooves are disposed on the outer wall of the first filler; there is an interference fit between the protrusions and the grooves.

4. The composite material according to claim 3, characterized in that, the protrusion includes a first surface and a second surface that are oppositely arranged, both the first surface and the second surface are arranged parallel to the center line of the first accommodation channel, one end of the first surface and the second surface is connected to the inner wall of the housing, and the other end of the first surface and the second surface intersects or is parallel.

5. The composite material according to any one of claims 2-4, characterized in that, both the protrusions and the grooves are multiple, and each protrusion is engaged with one groove.

6. The composite material according to any one of claims 1-5, characterized in that, the housing includes at least one of pure titanium, titanium alloy, stainless steel, and alloy steel.

7. The composite material according to any one of claims 1-6, characterized in that, the first filler includes a hard aluminum alloy, and the Vickers hardness of the hard aluminum alloy is greater than or equal to 120 HV.

8. The composite material according to any one of claims 1-6, characterized in that, the first filler includes a decorative anodized aluminum alloy.

9. The composite material according to any one of claims 1-6, characterized in that, the first filler includes a first aluminum matrix composite material, and the first aluminum matrix composite material includes pure aluminum or an aluminum alloy, and at least one of the following: silicon carbide, aluminum oxide, boron carbide, titanium diboride, graphene, carbon nanotubes, graphite, and diamond.

10. The composite material according to claim 9, characterized in that, the mass percentage of silicon carbide in the first aluminum matrix composite material is less than 65%.

11. The composite material according to claim 10, characterized in that, the silicon carbide in the first aluminum matrix composite material includes submicron-sized first silicon carbide particles and micron-sized first silicon carbide particles; wherein, the mass percentage of the submicron-sized first silicon carbide particles in the first aluminum matrix composite material is 0-20%, and the mass percentage of the micron-sized first silicon carbide particles in the first aluminum matrix composite material is 5%-40%.

12. The composite material according to claim 11, characterized in that, In the cumulative particle size distribution of the submicron-sized first silicon carbide particles, D50 is 0.3 μm - 1.0 μm; in the cumulative particle size distribution of the micron-sized silicon carbide particles, D50 is 3 μm - 20 μm; in the cumulative particle size distribution of the aluminum alloy, D50 is less than or equal to 20 μm.

13. The composite material according to any one of claims 1 - 12, characterized in that the composite material further includes a second filler. A second accommodation channel is provided in the first filler, and the center line of the second accommodation channel is parallel to the center line of the first accommodation channel; the second filler is disposed in the second accommodation channel, and the second filler is combined with the first filler, and the combination includes metallurgical bonding.

14. The composite material according to claim 13, characterized in that the second filler includes a second aluminum matrix composite material, and the mass percentage of silicon carbide in the second aluminum matrix composite material is less than 65%.

15. The composite material according to claim 14, characterized in that the silicon carbide in the second aluminum matrix composite material includes submicron-sized second silicon carbide particles and micron-sized second silicon carbide particles; wherein, the mass percentage of the submicron-sized second silicon carbide particles in the second aluminum matrix composite material is 0 - 10%, and the mass percentage of the micron-sized second silicon carbide particles in the second aluminum matrix composite material is 15% - 50%.

16. The composite material according to claim 15, characterized in that in the cumulative particle size distribution of the submicron-sized second silicon carbide particles, D50 is 0.5 μm - 1.0 μm, and in the cumulative particle size distribution of the micron-sized second silicon carbide particles, D50 is 3 μm - 20 μm.

17. The composite material according to any one of claims 13 - 16, characterized in that the elastic modulus of the first filler is greater than or equal to 85 GPa, and the elastic modulus of the second filler is greater than or equal to 110 GPa.

18. The composite material according to any one of claims 13 - 17, characterized in that the elongation of the first filler is greater than 3%, and the elongation of the second filler is greater than 0.2%.

19. A method for preparing a composite material, characterized in that the method includes: preparing a housing that encloses a first accommodation channel; preparing a first filler; installing the first filler in the first accommodation channel, and the first filler is combined with the inner wall of the first accommodation channel, and the combination includes metallurgical bonding.

20. The preparation method according to claim 19, characterized in that the step of installing the first filler in the first accommodation channel includes: extruding the housing and the first filler, and the housing and the first filler are connected by mutually engaging protrusions and grooves, so that the housing and the first filler are in interference fit.

21. The preparation method according to claim 20, characterized in that the step of extruding the housing and the first filler includes: Isostatic pressing treatment is performed on the outer shell and the first filling body.

22. The preparation method according to claim 21, wherein, the isostatic pressing treatment on the outer shell and the first filling body includes: Extruding according to a predetermined extrusion ratio, and heating the outer shell and the first filling body while extruding.

23. The preparation method according to any one of claims 19-22, wherein, the preparation of the outer shell includes: Providing a first rod, forming a first accommodating channel in the first rod, and the center line of the first accommodating channel is parallel to the center line of the first rod; Forming a protrusion on the inner wall of the first accommodating channel, and the protrusion extends in a direction parallel to the center line of the first rod.

24. The preparation method according to any one of claims 19-23, wherein, the preparation of the first filling body includes: Providing a second rod, forming a groove on the outer wall of the second rod, and the groove extends in a direction parallel to the center line of the second rod; The installation of the first filling body in the first accommodating channel further includes: inserting the second rod into the first accommodating channel in a direction parallel to the center line of the first rod, and embedding the protrusion into the groove.

25. The preparation method according to any one of claims 19-24, wherein, the preparation of the first filling body further includes: Forming a second accommodating channel in the first filling body, and the center line of the second accommodating channel is parallel to the center line of the first accommodating channel; The method further includes: Preparing a second filling body, installing the second filling body in the second accommodating channel, and combining the second filling body with the second accommodating channel, and the combination includes metallurgical bonding.

26. A middle frame, the middle frame is made of the composite material according to any one of claims 1-18, wherein, the middle frame includes a frame and a middle plate, the middle plate is connected to the frame, and the middle plate is configured to be disposed inside the electronic device; the frame includes the outer shell, and the middle plate includes the first filling body.

27. The middle frame according to claim 26, wherein, the composite material further includes a second filling body, a second accommodating channel is provided in the first filling body, and the center line of the second accommodating channel is parallel to the center line of the first accommodating channel; the second filling body is disposed in the second accommodating channel, and the second filling body is combined with the first filling body, and the combination includes metallurgical bonding; the middle plate includes a battery area and a non-battery area, the battery area includes the second filling body, and the non-battery area includes the first filling body.

28. A middle frame, the middle frame is made of the composite material according to any one of claims 1-18, wherein, the middle frame includes a frame and a back cover, the frame is connected to the back cover, and the back cover is configured to be located on the back of the electronic device; the frame includes the outer shell, and the back cover includes the first filling body.

29. The middle frame according to claim 28, wherein, The composite material further includes a second filler. A second accommodation channel is provided in the first filler, and the center line of the second accommodation channel is parallel to the center line of the first accommodation channel. The second filler is disposed in the second accommodation channel, and the second filler is combined with the first filler, and the combination includes metallurgical bonding. The rear cover includes a battery area and a non-battery area. The battery area includes the second filler, and the non-battery area includes the first filler.

30. The middle frame according to claim 28 or 29, wherein, A decorative layer is provided on at least a part of the outer surface of the rear cover, and the decorative layer is made of anodized aluminum alloy.

31. A method for manufacturing a middle frame, wherein, The method includes: Manufacturing a composite material by using the manufacturing method of the composite material according to any one of claims 19-25; Cutting the composite material along a square perpendicular to the center line of the first accommodation channel to form a plate body; Machining the plate body so that the outer shell forms the frame of the middle frame, and the first filler forms the middle plate of the middle frame.

32. A method for manufacturing a middle frame, wherein, The method includes: Manufacturing a composite material by using the manufacturing method of the composite material according to any one of claims 19-25; Cutting the composite material along a square perpendicular to the center line of the first accommodation channel to form a plate body; Machining the plate body so that the outer shell forms the frame of the middle frame, and the first filler forms the rear cover of the middle frame.

33. The method according to claim 32, wherein, The machining of the plate body so that the outer shell forms the frame of the middle frame, and the first filler forms the rear cover of the middle frame further includes: Anodizing at least a part of the outer surface of the rear cover to obtain a decorative layer.

34. An electronic device, wherein, The electronic device includes a display screen, a battery, and the middle frame according to claim 26 or claim 27, or the middle frame according to any one of claims 28-30, and the display screen and the battery are disposed on the middle frame.

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