Electronic device housing, manufacturing method therefor, and electronic device

Abstract

Provided in the present application are an electronic device housing, a manufacturing method therefor, and an electronic device. The electronic device housing comprises an outer metal layer and an inner metal layer which are stacked, the outer metal layer and the inner metal layer being made of different materials. The electronic device housing has at least one first R angle, the first R angle being greater than or equal to 0.1 mm. At the first R angle, a bonding line is provided at the junction of cross sections of the outer metal layer and the inner metal layer, the straightness of the bonding line being less than 0.1 mm.

Description

Electronic device shell, preparation method thereof and electronic device

[0001] Cross-references to related documents

[0002] The present application claims priority to the Chinese patent application No. 202410718449.5, filed on June 04, 2024, and entitled "Electronic device shell, preparation method thereof and electronic device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of metal materials, in particular to an electronic device shell, a preparation method thereof and an electronic device. BACKGROUND

[0004] At present, in order to make the electronic device shell have good mechanical properties and light weight, a method of compounding a metal with small density and a metal with good mechanical properties is usually adopted. However, the current composite metal still has problems such as irregular bonding lines at the interface between different metals during the stamping forming process of preparing the electronic device shell, and the range of R angle is limited. SUMMARY

[0005] In view of this, the present application provides an electronic device shell, a preparation method thereof and an electronic device. The electronic device shell has a small R angle, can form a structure close to a right angle, and the thicknesses of the outer metal layer and the inner metal layer are uniform, the straightness of the bonding line at the interface between the two is small, and the comprehensive mechanical properties of the electronic device shell are excellent.

[0006] In a first aspect, the present application provides an electronic device shell, which comprises an outer metal layer and an inner metal layer arranged in layers, the outer metal layer and the inner metal layer are metal layers of different materials; the electronic device shell has at least one first R angle, the first R angle is greater than or equal to 0.1 mm; at the first R angle, the interface between the outer metal layer and the inner metal layer has a bonding line, and the straightness of the bonding line is less than 0.1 mm.

[0007] In an embodiment of the present application, the diffusion depth between the metals at the interface between the outer metal layer and the inner metal layer is 0.1-10 μm.

[0008] In an embodiment of the present application, the average grain size deviation of the outer metal layer is less than or equal to 10%.

[0009] In an embodiment of the present application, the thickness of the outer metal layer is greater than or equal to 0.2 mm.

[0010] In an embodiment of the present application, the outer metal layer comprises at least one of aluminum and its alloys, titanium and its alloys, iron and its alloys, and zirconium and its alloys; and the inner metal layer comprises at least one of aluminum and its alloys, copper and its alloys, zinc and its alloys, and magnesium and its alloys.

[0011] In an embodiment of the present application, the outer metal layer has an elastic modulus greater than or equal to 70 GPa, and the elastic modulus of the outer metal layer is greater than that of the inner metal layer.

[0012] In an embodiment of the present application, the outer metal layer has a yield strength greater than or equal to 150 MPa, and the strength of the outer metal layer is greater than that of the inner metal layer.

[0013] In an embodiment of the present application, the inner metal layer has a thermal conductivity greater than or equal to 100 W·m -1 ·k -1 , and the thermal conductivity of the inner metal layer is greater than that of the outer metal layer.

[0014] In an embodiment of the present application, the inner metal layer has a density greater than or equal to 1.2 g / cm 3 , and the density of the inner metal layer is less than that of the outer metal layer.

[0015] In an embodiment of the present application, the inner metal layer has a bonding strength greater than or equal to 70 MPa with the outer metal layer.

[0016] The electronic device shell provided by the present application has a small R angle, can form a structure close to a right angle, and has uniform thicknesses of the outer metal layer and the inner metal layer, small straightness of the bonding line at the interface, and excellent comprehensive mechanical properties.

[0017] In a second aspect, the present application provides a preparation method of the electronic device shell provided in the first aspect, comprising:

[0018] providing a to-be-stamped composite metal, the to-be-stamped composite metal comprising a first metal layer and a second metal layer stacked; the first metal layer is used to form the outer metal layer, and the second metal layer is used to form the inner metal layer;

[0019] stamping the to-be-stamped composite metal in a stamping die, and then performing heat treatment to obtain an electronic device shell blank;

[0020] milling the electronic device shell blank to obtain an electronic device shell.

[0021] In an embodiment of the present application, the edge of the first metal layer away from the side of the second metal layer has at least one second R-angle, the second R-angle satisfies: 3t1≤second R-angle≤6t1; the edge of the second metal layer away from the side of the first metal layer has a third R-angle corresponding to the position of the second R-angle, the third R-angle satisfies: 7t2≤third R-angle≤13t2, wherein t1 is the thickness of the first metal layer, and t2 is the thickness of the second metal layer.

[0022] In an embodiment of the present application, the second R-angle transitions to the third R-angle corresponding to the position of the second R-angle to form a slope, the thickness of the slope gradually decreases from the second metal layer to the first metal layer.

[0023] In an embodiment of the present application, the slope angle is greater than or equal to 10° and less than or equal to 40°, the distance L1 of the slope from the vertex of the second R-angle to the vertex of the third R-angle is ≥2t, and the slope height h is ≤t, wherein t is the thickness of the composite metal to be punched.

[0024] In an embodiment of the present application, the punch die comprises an upper die and a lower die, the lower die comprises a groove, a convex portion is arranged around the position where the inner wall bottom of the groove connects with the side wall, the first metal layer of the composite metal to be punched contacts with the groove of the lower die, the convex portion comprises a horizontal boss, the width L2 of the horizontal boss is ≥t2, and the height D of the horizontal boss satisfies: 1 / 4t1≤D≤t1.

[0025] In an embodiment of the present application, the punch temperature T1 of the punching process satisfies: 1 / 4T m ≤T1<T m , wherein T m is the minimum value of the melting point of the outer metal layer and the melting point of the inner metal layer; the punch time of the punching process is 3s-15s; and the pressure holding time of the punching process is 30s-60s.

[0026] In an embodiment of the present application, the temperature T2 of the heat treatment satisfies: T2≤1 / 3T m ; and the time of the heat treatment is 30min-120min.

[0027] In an embodiment of the present application, the milling is further followed by an injection molding process.

[0028] The preparation method of the electronic device shell provided in the application is novel. The thickness of the outer metal layer and the inner metal layer of the prepared electronic device shell is uniform, the straightness of the bonding line at the cross-section bonding site is small, the comprehensive mechanical properties of the electronic device shell are excellent, and the grain structure of the electronic device shell is uniform, which facilitates subsequent uniform coloring.

[0029] In a third aspect, the application provides an electronic device shell, which is used in an electronic device middle frame.

[0030] In a fourth aspect, the application provides an electronic device, which comprises the electronic device shell provided in the first aspect or the third aspect, or the electronic device shell prepared by the preparation method provided in the second aspect.

[0031] The electronic device shell provided in the application has excellent mechanical properties and heat dissipation performance and is low in density and light in weight, and has good mechanical properties, good user experience, and long service life. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. The specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0033] FIG. 1 is a schematic diagram of a partial cross-section structure of an electronic device shell provided in an embodiment of the application;

[0034] FIG. 2 is a flowchart of a preparation method of an electronic device shell provided in an embodiment of the application;

[0035] FIG. 3 is a top view of a punching plane of a composite metal to be punched in the preparation method provided in an embodiment of the application;

[0036] FIG. 4 is an enlarged side view of the thickness direction of the A area of the composite metal to be punched in FIG. 3;

[0037] FIG. 5 is a schematic diagram of a partial cross-section structure of a punching die in the preparation method provided in an embodiment of the application;

[0038] FIG. 6 is a metallographic representation of the cross-section bonding site of the outer metal layer and the inner metal layer of the electronic device shell prepared in Example 1 of the application;

[0039] FIG. 7 is a metallographic representation of the grain structure of the extruded area of the outer metal layer and the non-extruded area of the outer metal layer of the electronic device shell prepared in Example 1 of the application;

[0040] FIG. 8 is an EDS (Energy Dispersive Spectroscopy) characterization result of the interface between the outer metal layer and the inner metal layer of the electronic device shell prepared in Example 1 of the present application.

[0041] BRIEF DESCRIPTION OF DRAWINGS: 100-electronic device shell; 101-outer metal layer; 102-inner metal layer; 200-punching die; 201-lower die; 202-upper die; 11-outer metal layer precursor; 12-inner metal layer precursor; 10-metal to be punched; 1-first metal layer; 2-second metal layer. DETAILED DESCRIPTION

[0042] At present, in order to make the electronic device shell have good mechanical properties and lighter quality, the method of compounding the metal with smaller density and the metal with better mechanical properties is usually adopted. However, the forming method of the electronic device shell at present is usually pressure casting, casting forming or adopting the method of powder metallurgy to form multiple times, and the product structure is divided into two or more parts for processing, and then the parts are combined into a whole. The heterogeneous composite metal has the advantage of one-piece forming, which can effectively improve the combination of the electronic product shell and shorten the process flow. However, there are still problems such as irregular bonding line at the interface between the heterogeneous metals in the electronic device shell prepared in the punching forming process, uneven grain structure of the composite metal, poor comprehensive mechanical properties, and limited range of R angle.

[0043] With the change of the design style of electronic products in recent years, the square right-angle frame design of the electronic device shell is more and more popular. There are usually two forming methods to achieve the approximate right-angle frame, one is CNC machining, i.e. computer numerical control precision machining, and the other is punching forming. Due to the particularity of the heterogeneous composite metal, only the punching forming method can be adopted, and the upsetting extrusion process is needed to form the approximate right-angle design. The metal fluidity of different metal layers of the electronic device shell compounded by different metal materials is different, which will cause problems such as irregular bonding line at the interface between the heterogeneous metals in the cross section of the prepared electronic device shell, uneven grain structure of the composite metal, poor comprehensive mechanical properties, and limited range of R angle.

[0044] In view of the above problems, the present application provides an electronic device shell and a preparation method thereof and an electronic device. The R angle of the electronic device shell is small, which can form an approximate right-angle structure, and the thickness of the outer metal layer and the inner metal layer is uniform, the straightness of the bonding line at the cross section is small, and the comprehensive mechanical properties of the electronic device shell are excellent.

[0045] Referring to FIG. 1, a schematic diagram of a partial cross-sectional structure of an electronic device shell is provided according to an embodiment of the present application. The electronic device shell 100 provided by the present application includes an outer metal layer 101 and an inner metal layer 102 arranged in a stack, and the outer metal layer 101 and the inner metal layer 102 are metal layers of different materials. In an embodiment of the present application, the electronic device shell 100 has at least one first R angle, and the first R angle is greater than or equal to 0.1 mm. Specifically, the size of the first R angle can be, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.5 mm, or 1 mm. The electronic device shell provided by the present application can minimize the size of the first R angle to 0.1 mm, and control it within a suitable range to obtain a structure close to a right angle, thereby improving the aesthetics of the electronic device shell. In an embodiment of the present application, at the first R angle, the cross-sectional joint of the outer metal layer 101 and the inner metal layer 102 has a joint line, and the straightness of the joint line is less than 0.1 mm. Since the outer metal layer 101 and the inner metal layer 102 are metal layers of different materials, the cross-sectional joint of the two layers in the thickness direction will form a joint line. In the present application, the straightness of the joint line refers to the total amount of variation allowed by the joint line in the cross-sectional plane of the electronic device shell in the thickness direction, that is, the width of the tolerance band. The straightness of the joint line can be measured and calculated by the metallographic test method: a part of the sample is cut, polished along the thickness direction of the sample, and then the joint line of the outer metal layer and the inner metal layer is observed and measured by a metallographic microscope, and the range is recorded as the straightness of the joint line. The present application controls the straightness of the joint line at the cross-sectional joint of the outer metal layer and the inner metal layer within a smaller range, effectively solves the problem of poor flatness of the joint line between the heterogeneous metals in the current electronic device shell, and can be beneficial to make the thickness of the outer metal layer and the inner metal layer of the electronic device shell more uniform, thereby improving the uniformity of the overall performance of the electronic device shell and the uniformity of subsequent oxidation coloring, improving the mechanical properties and aesthetics of the electronic device, and controlling the straightness of the joint line within a suitable range can also improve the bonding force between the outer metal layer and the inner metal layer, preventing the two heterogeneous metal layers from peeling or falling off during processing or use. Specifically, the straightness of the joint line can be, for example, 0.01 mm, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, etc.

[0046] In an embodiment of the present application, since the outer metal layer and the inner metal layer are metal layers of different materials, there is a micron-level intermetallic diffusion layer formed by intermolecular thermal motion at the interface between the outer metal layer 101 and the inner metal layer 102. The intermetallic diffusion layer includes both the first metal in the outer metal layer and the second metal in the inner metal layer, that is, the first metal element of the outer metal layer and the second metal element of the inner metal layer can be measured at each position in the intermetallic diffusion layer between the outer metal layer and the inner metal layer by EDS (Energy Dispersive Spectroscopy). The thickness of the intermetallic diffusion layer corresponds to the diffusion depth between the metals, and the diffusion depth between the metals is specifically the depth in the thickness direction of the electronic device shell. In an embodiment of the present application, the diffusion depth between the metals is 0.1-10 μm. Controlling the diffusion depth between the metals between the outer metal layer and the inner metal layer in a smaller range can make the heterogeneous metal interface bonding better, thereby improving the bonding force between the outer metal layer and the inner metal layer of the electronic device shell and improving the comprehensive mechanical properties of the electronic device shell, forming a nearly right-angle structure, effectively preventing the electronic device shell from warping, curling, and poor flatness after forming due to the difference in thermal deformation performance of heterogeneous metals, and also making the structure uniform at the R angle, obtaining a product with uniform color after subsequent anodic oxidation coloring, and improving the appearance of the product. Specifically, the diffusion depth between the metals can be, for example, 0.1 μm, 0.2 μm, 0.3 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm.

[0047] In an embodiment of the present application, the average grain size deviation of the grain structure of the outer metal layer 101 in the electronic device shell 100 is less than or equal to 10%. The average grain size is a measure of the size of the metal grain structure, which is generally represented by the average area and average diameter of the grains, and is measured by a metallographic microscope. The average grain size deviation in the present application refers to the difference in the average grain size at two arbitrary positions, that is, the absolute value of the difference in the grain size at two arbitrary positions divided by the average grain size. In an embodiment of the present application, the measurement position of the average grain size can be any position of the outer metal layer 101 of the electronic device shell 100, specifically, the inside of the extruded area of the outer metal layer 101, the inside of the non-extruded area of the outer metal layer 101, or the extruded area of the outer metal layer 101 and the non-extruded area of the outer metal layer 101. The electronic device shell of the present application is obtained by stamping a heterogeneous composite metal, and the design of forming an approximately right-angle R corner also requires a process of upsetting and extruding. The average grain size deviation of the grain structure of the parts of the electronic device shell of the present application subjected to upsetting and extrusion and not subjected to upsetting and extrusion is less than or equal to 10%. The overall grain structure size of the electronic device shell of the present application is basically uniform, the size is uniform, and thus the uniformity of the mechanical properties of the electronic device shell can be improved, the mechanical strength and service life of the electronic device shell are improved; and when the electronic device shell is subjected to subsequent anodic oxidation coloring treatment, the corrosion degree of each part is similar, and thus a colored electronic device shell with uniform coloring can be obtained, and the aesthetic appearance of the electronic device shell is improved.

[0048] In an embodiment of the present application, the thickness of the outer metal layer is greater than or equal to 0.2 mm. The electronic device shell provided by the present application can control the minimum thickness of the outer metal layer to 0.2 mm. Specifically, the thickness of the outer metal layer can be, for example, 0.2 mm, 0.25 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.8 mm, or 1 mm. The electronic device shell provided by the present application can make the thickness of the outer metal layer exposed to the outside as thin as 0.2 mm, so as to realize the light weight of the product as much as possible while ensuring the mechanical properties of the electronic device shell, improve the material utilization rate, realize green development, and improve the user experience.

[0049] In an embodiment of the present application, the bonding strength between the outer metal layer and the inner metal layer is greater than or equal to 70 MPa. By controlling the bonding strength between the outer metal layer and the inner metal layer to be greater than or equal to 70 MPa, the comprehensive mechanical properties of the electronic device shell can be improved, the outer metal layer and the inner metal layer can be prevented from peeling off or falling off during use, and the service life of the electronic device shell can be prolonged. In an embodiment of the present application, the bonding strength between the outer metal layer and the inner metal layer can be measured by a shear test. Specifically, the bonding strength between the outer metal layer and the inner metal layer can be, but is not limited to, 70 MPa, 80 MPa, 90 MPa, 100 MPa, 105 MPa, 110 MPa, 120 MPa, 130 MPa, 150 MPa, 180 MPa, or 200 MPa, etc.

[0050] In an embodiment of the present application, the outer metal layer comprises at least one of magnesium and its alloys, aluminum and its alloys, copper and its alloys, iron and its alloys, zirconium and its alloys, titanium and its alloys, manganese and its alloys, chromium and its alloys, and zinc and its alloys; and the inner metal layer comprises at least one of magnesium and its alloys, aluminum and its alloys, copper and its alloys, iron and its alloys, zirconium and its alloys, titanium and its alloys, manganese and its alloys, chromium and its alloys, and zinc and its alloys.

[0051] In an embodiment of the present application, the outer metal layer can serve as an outer surface metal layer exposed outside the electronic device shell. When the electronic device shell is, for example, an electronic device middle frame, the outer metal layer faces the outside of the electronic device. In some specific embodiments, the outer metal layer comprises at least one of aluminum and its alloys, titanium and its alloys, iron and its alloys, and zirconium and its alloys. In some specific embodiments, the iron alloy comprises a steel, i.e., an iron-carbon alloy. In some embodiments, the elastic modulus of the outer metal layer is greater than or equal to 70 GPa, and the elastic modulus of the outer metal layer is greater than the elastic modulus of the inner metal layer. In some embodiments, the yield strength of the outer metal layer is greater than or equal to 150 MPa, and the strength of the outer metal layer is greater than the strength of the inner metal layer. When the outer metal layer serves as an outer surface metal layer exposed outside, controlling its elastic modulus and strength within a suitable range can provide the electronic device shell with better mechanical properties to cope with the impact when the electronic device shell encounters a sharp object or falls.

[0052] In an embodiment of the present application, the inner metal layer can serve as an inner surface metal layer not exposed outside the electronic device shell. When the electronic device shell is, for example, an electronic device middle frame, the inner metal layer faces the inside of the electronic device. In some specific embodiments, the inner metal layer comprises at least one of aluminum and its alloys, copper and its alloys, zinc and its alloys, and magnesium and its alloys. In some embodiments, the thermal conductivity of the inner metal layer is greater than or equal to 100 W·m -1 ·k-1 and the thermal conductivity of the inner metal layer is greater than the thermal conductivity of the outer metal layer. In some embodiments, the density of the inner metal layer is greater than or equal to 1.2 g / cm3. 3 and the density of the inner metal layer is less than the density of the outer metal layer. Controlling the thermal conductivity and the density of the inner metal layer within a suitable range can provide better heat dissipation performance and reduce the weight of the entire electronic device shell.

[0053] In an embodiment of the present application, the first metal layer comprises a titanium alloy, the second metal layer comprises an aluminum alloy, and the connecting layer comprises die-cast aluminum. The titanium alloy has good mechanical properties. If the titanium alloy is selected for the first metal layer, the resulting composite metal can be used as the electronic device shell, which can effectively protect the internal devices of the electronic device shell. In addition, the titanium alloy has good wear resistance and corrosion resistance, which can improve the service life of the composite metal. The aluminum alloy has good thermal conductivity and a small density. If the aluminum alloy is selected for the second metal layer, the resulting composite metal can be used as the electronic device shell, which can effectively dissipate heat and reduce the overall mass of the electronic device shell. The die-cast aluminum has a hardness similar to that of the aluminum alloy. If the die-cast aluminum is used as the connecting layer between the first metal layer of the titanium alloy and the second metal layer of the aluminum alloy, the bonding force between the first metal layer and the second metal layer can be improved.

[0054] In an embodiment of the present application, the connecting layer is disposed between the outer metal layer and the inner metal layer. The connecting layer can comprise, but is not limited to, a metal or a resin. In some specific embodiments, the metal can be at least one of magnesium and its alloys, aluminum and its alloys, zinc and its alloys, and copper and its alloys. The resin can be at least one of polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyamide (PA), polyphthalamide (PPA), polypropylene (PP), polycarbonate (PC), polyphenylene sulfone (PPSU), and polyether ether ketone (PEEK). The connecting layer disposed between the outer metal layer and the inner metal layer can improve the bonding force between the outer metal layer and the inner metal layer.

[0055] The present application also provides a method for manufacturing an electronic device shell. Referring to FIG. 2, the flow chart of the method for manufacturing an electronic device shell according to an embodiment of the present application comprises the following steps:

[0056] S101, providing a composite metal to be stamped, the composite metal to be stamped comprising a first metal layer and a second metal layer stacked and arranged; the first metal layer is used to form an outer metal layer, and the second metal layer is used to form an inner metal layer;

[0057] S102, placing the composite metal to be stamped in a stamping die for stamping treatment, and then performing heat treatment to obtain an electronic device shell blank;

[0058] S103, milling the electronic device shell blank to obtain the electronic device shell.

[0059] In step S101, referring to FIG. 3 and FIG. 4, the composite metal to be punched 10 provided in an embodiment of the present application, FIG. 3 is a top view of the plane to be punched of the composite metal to be punched 10, and FIG. 4 is an enlarged side view of the thickness direction of area A of the composite metal to be punched 10 in FIG. 3. In an embodiment of the present application, the composite metal to be punched 10 is a flat plate, and the composite metal to be punched 10 includes a first metal layer 1 and a second metal layer 2 stacked, wherein the first metal layer 1 is used to form an outer metal layer 101 of the electronic device shell 100, and the second metal layer is used to form an inner metal layer of the electronic device shell 100.

[0060] As shown in FIG. 3, in an embodiment of the present application, the edge of the side of the first metal layer 1 away from the second metal layer 2 has at least one second R angle, and the thickness of the first metal layer 1 is defined as t1, and the second R angle satisfies: 3t1≤second R angle≤6t1. Specifically, the size of the second R angle may, for example, be 3t1, 4t1, 5t1, 6t1. In an embodiment of the present application, the edge of the side of the second metal layer 2 away from the first metal layer 1 has a third R angle at the corresponding position of the second R angle described above, and there is a third R angle corresponding to each second R angle in the composite metal to be punched. The thickness of the second metal layer 2 is defined as t2, and the third R angle satisfies: 7t2≤third R angle≤13t2. Specifically, the size of the third R angle may, for example, be 7t2, 8t2, 9t2, 10t2, 11t2, 12t2, 13t2. By specially designing the second R angle and the third R angle in the composite metal to be punched according to the thickness of the metal layer, the present application can obtain a smaller R angle that is approximately a right angle after the composite metal to be punched is punched and extruded, and can ensure that the bonding line between the corresponding obtained outer metal layer and inner metal layer has good flatness.

[0061] As can be seen from FIG. 3, the second R angle transitions to the third R angle at the corresponding position of the second R angle to form a slope, i.e., the part enclosed by the dashed line in FIG. 3, the thickness gradually decreases from the second metal layer to the first metal layer in the direction of the slope, and the top of the slope is located at the second R angle, and the bottom of the slope is located at the third R angle corresponding to the second R angle.

[0062] In an embodiment of the present application, the slope angle a of the slope is greater than or equal to 10° and less than or equal to 40°, and specifically, the slope angle a may, for example, be 10°, 15°, 20°, 25°, 30°, 35°, or 40°. The total thickness t of the composite metal to be punched is defined as t = t1 + t2, where t1 is the thickness of the first metal layer and t2 is the thickness of the second metal layer. In an embodiment of the present application, the distance L1 of the slope from the second R-angle vertex to the third R-angle vertex satisfies L1≥2t, and specifically, the distance L1 may, for example, be 2t, 2.2t, 2.5t, 2.8t, 3t, 4t, or 5t. In an embodiment of the present application, the slope height h of the slope satisfies h≤t, and specifically, the slope height h may, for example, be 0.3t, 0.4t, 0.5t, 0.6t, 0.7t, 0.8t, 0.9t, or t. By performing special slope design on the composite metal to be punched between the corresponding second R-angle and third R-angle and controlling the relevant parameters of the slope within a suitable range, the first R-angle obtained after the composite metal to be punched is punched and upset is approximately a right angle, and the bonding line between the outer metal layer and the inner metal layer has good flatness.

[0063] In step S102, referring to FIG. 5, a partial cross-sectional structure schematic diagram of the punching die 200 in the preparation method provided in an embodiment of the present application is shown. The punching die 200 includes an upper die 202 and a lower die 201. The lower die 201 includes a groove for placing the composite metal to be punched. A convex portion is arranged around the position where the inner wall bottom of the groove connects with the side wall. During punching, the first metal layer of the composite metal to be punched is in contact with the groove of the lower die. In the embodiment of the present application, the convex portion protrudes to the side of the groove opening.

[0064] In the embodiment of the present application, the convex portion includes a horizontal boss, which is a convex portion part with consistent height in the horizontal direction, that is, the side surface of the horizontal boss facing the groove opening is a plane. For the convenience of description, the direction along the side wall of the groove to the center of the groove is defined as the first direction. In the embodiment of the present application, the width L2 of the horizontal boss is the length of the horizontal boss in the first direction, and the width L2 of the horizontal boss satisfies T2≥t2, and specifically, the width L2 of the horizontal boss may, for example, be t2, 1.2t2, 1.5t2, 1.8t2, 2t2, 3t2, or 4t2. In the embodiment of the present application, the height D of the horizontal boss is the vertical straight line distance from the side surface of the horizontal boss facing the groove opening to the part of the inner wall bottom of the groove where no convex portion is arranged, and the height D of the horizontal boss satisfies 1 / 4t1≤D≤t1, and specifically, the height D of the horizontal boss may, for example, be 1 / 4t1, 0.3t1, 0.4t1, 0.5t1, 0.6t1, 0.7t1, 0.8t1, 0.9t1, or t1.

[0065] In some embodiments of the present application, the protrusion further comprises a first transition portion connecting the horizontal boss and the side wall of the groove, the first transition portion being an arc surface or an inclined surface towards one side surface of the groove opening in the first direction, and / or a second transition portion connecting the horizontal boss and the portion of the bottom of the groove without the protrusion, the second transition portion being an arc surface or an inclined surface towards one side surface of the groove opening. In the present application, by designing the special protrusion structure of the lower die of the stamping die and cooperating with the specially designed composite metal to be stamped, the first R angle of approximately 90 degrees obtained after the composite metal to be stamped is subjected to stamping and upsetting and extruding treatment, and the outer metal layer precursor 11 obtained after the first metal layer 1 of the composite metal to be stamped 10 is subjected to stamping, and the inner metal layer precursor 12 obtained after the second metal layer 2 of the composite metal to be stamped 10 is subjected to stamping treatment.

[0066] The minimum value of the melting point of the outer metal layer and the melting point of the inner metal layer is defined as T m , wherein the material and the melting point of the first metal layer 1, the outer metal layer precursor 11 and the outer metal layer 101 are the same, and the material and the melting point of the second metal layer 2, the inner metal layer precursor 12 and the inner metal layer 102 are the same.

[0067] In an embodiment of the present application, the stamping temperature T1 of the stamping treatment satisfies: 1 / 4T m ≤T1<T m , specifically, the stamping temperature of the stamping treatment may, for example, be 1 / 4T m , 0.3T m , 0.4T m , 0.5T m , 0.6T m , 0.7T m , 0.8T m , 0.9T m , T m . In an embodiment of the present application, the stamping time of the stamping treatment is 3s-15s, and the holding time of the stamping treatment is 30s-60s. Specifically, the stamping time of the stamping treatment may, for example, be 3s, 4s, 5s, 6s, 8s, 9s, 10s, 12s, 14s, 15s, and the holding time of the stamping treatment may, for example, be 30s, 35s, 40s, 45s, 50s, 55s, 60s. Controlling the relevant parameters of the stamping treatment within a suitable range can promote the stamping and integral molding of the electronic device shell and obtain an electronic device shell with a suitable R angle and good hetero-metal combination.

[0068] In an embodiment of the present application, the temperature T2 of the heat treatment satisfies: T2≤1 / 3T m , specifically, the temperature T2 of the heat treatment may, for example, be 0.1T m , 0.15T m , 0.2Tm 0.25T m 0.3T m 1 / 3T m In an embodiment of the present application, the time of heat treatment is 30 min-120 min. Specifically, the heat treatment may, for example, be 30 min, 40 min, 50 min, 60 min, 80 min, 100 min, 110 min or 120 min. Since the upsetting and extruding in the stamping forming process will cause the incoordination of metal deformation at the deformed and undeformed positions, resulting in uneven distribution of grain structure and color difference on the surface of the electronic device shell after subsequent anodic oxidation coloring treatment, the present application can effectively improve the appearance quality of the electronic device shell without affecting the bonding force and deformation performance of the electronic device shell by reasonably designing the parameters of heat treatment.

[0069] In step S103, in an embodiment of the present application, the milling is followed by injection molding. In an embodiment of the present application, the material of injection molding includes plastic and glass fiber. The plastic may, but is not limited to, include at least one of polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), acrylonitrile-styrene-diene copolymer (ABS), polyamide (PA), polyphthalamide (PPA), polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyaryletherketone (PEAK) and polyether ether ketone (PEEK). In an embodiment of the present application, the material of injection molding can be polybutylene terephthalate (PBT).

[0070] In an embodiment of the present application, the mass percentage of glass fiber in the material of injection molding is less than or equal to 55%. Specifically, the mass percentage of glass fiber may, but is not limited to, be less than or equal to 55%, less than or equal to 50%, less than or equal to 45%, less than or equal to 40%, less than or equal to 35%, less than or equal to 30% or less than or equal to 20%, etc. In an embodiment of the present application, the mass percentage of glass fiber can be 40%.

[0071] The preparation method of the electronic device shell provided by the present application adopts an integrated molding process, which has low preparation cost and short preparation period. Through special design of the parameters of the to-be-stamped composite metal, the stamping die and stamping and heat treatment, the thickness of the outer metal layer and the inner metal layer of the prepared electronic device shell is uniform, the straightness of the bonding line at the interface bonding position is small, the comprehensive mechanical properties of the electronic device shell are excellent, and the grain structure of the electronic device shell is uniform, which facilitates subsequent uniform coloring and effectively solves the problems of warping, edge curling and poor flatness of the electronic device shell after forming due to the difference in thermal deformation performance of heterogeneous metals.

[0072] The application further provides an electronic device shell used in an electronic device middle frame which is an integrated structure with an electronic device back cover.

[0073] The application further provides an electronic device comprising the electronic device shell provided in the foregoing or prepared by the preparation method provided in the foregoing, which can be a mobile phone, a tablet computer, a notebook computer, a wearable device (watch, bracelet), a digital camera, etc.

[0074] The electronic device shell provided by the application has excellent mechanical properties and heat dissipation performance and is low in density and light in weight, and has good mechanical properties, good user experience and long service life.

[0075] The effects of the technical scheme of the application are further described below through specific examples.

[0076] Embodiment 1

[0077] (1) A composite metal to be punched is provided, the composite metal to be punched comprising a first metal layer and a second metal layer stacked, the first metal layer being 6013 aluminum alloy, the thickness t1 of the first metal layer being 2.25 mm, and the R angle R1 of the first metal layer being 10 mm; the second metal layer being AZ31 magnesium alloy, the thickness t2 of the second metal layer being 3.55 mm, and the R angle R2 of the second metal layer being 35 mm; the composite metal to be punched comprising a second R angle for forming a first R angle, the thickness of the second R angle being gradually smaller in the direction of the second R angle along the center of the composite metal to be punched to form a slope, the slope angle being 20°, the slope length L1 being 12 mm, and the slope height h being 3.5 mm;

[0078] (2) The composite metal to be punched is placed in a punching die for punching treatment, the lower die of the punching die comprising a groove, a convex portion being annularly arranged at the position where the bottom of the groove is connected with the side wall, the width L2 of the convex portion being 4.5 mm, and the height D of the convex portion being 1.4 mm; the die is heated for 30 min at a temperature of 200℃, and then the punching treatment is performed, the punching temperature being 200℃, the punching time being 5 s, and the pressure maintaining time being 60 s;

[0079] (3) The material obtained after punching is further subjected to heat treatment at a temperature of 180℃ for 90 min, and then naturally cooled to room temperature to obtain an electronic device shell blank;

[0080] (4) milling the prepared electronic device shell blank, milling off the remaining part of the outer metal layer precursor obtained after stamping the first metal layer except the part forming the frame body outer metal layer to form an aluminum alloy outer surface, and milling off the remaining part of the inner metal layer precursor obtained after stamping the second metal layer except the part forming the frame body inner metal layer to form a magnesium alloy inner cavity, to obtain an electronic device shell, wherein the thickness of the inner metal layer of the electronic device shell is greater than or equal to 0.4 mm, and the thickness of the outer metal layer is 0.3 mm.

[0081] By cutting the prepared electronic device shell along the thickness direction, the interface bonding of the outer metal layer and the inner metal layer at the first R corner of the electronic device shell is observed by using a metallographic microscope, and the obtained result is shown in FIG. 6. The straightness of the bonding line measured and calculated is 0.02 mm.

[0082] The grain structure of the extruded area of the outer metal layer and the non-extruded area of the outer metal layer of the prepared electronic device shell is observed by using a metallographic microscope, and the obtained result is shown in FIG. 7. The average grain size of the extruded area and the average grain size of the non-extruded area are measured and calculated respectively, and the average grain size deviation of the extruded area and the non-extruded area is calculated. The calculated result is ≤10%, and the structure types of the extruded area and the non-extruded area of the outer metal layer are consistent. As can be seen from FIG. 7, the grain structure types of the two areas are both matrix and precipitated phase, and the precipitated phase is uniformly distributed on the matrix.

[0083] The elements at the interface bonding of the outer metal layer and the inner metal layer are detected by EDS (Energy Dispersive Spectroscopy), and the positions of the magnesium element and the aluminum element are measured at the same time, which are the intermetallic diffusion layer. The thickness of the intermetallic diffusion layer corresponds to the intermetallic diffusion depth, and the intermetallic diffusion depth is specifically the depth along the thickness direction of the composite metal. The measured result is shown in FIG. 8. As can be seen from FIG. 8, the intermetallic diffusion depth between the outer metal layer and the inner metal layer in the electronic device shell of Example 1 is about 5 μm.

[0084] Example 2

[0085] The difference from Example 1 is that the first metal layer is TC4 titanium alloy.

[0086] Example 3

[0087] The difference from Example 1 is that the second metal layer is 316L stainless steel.

[0088] Example 4

[0089] The difference from Example 1 is that the temperature of the heat treatment is 210℃, and the time of the heat treatment is 60 min.

[0090] Example 5

[0091] The difference from Example 1 is that the temperature of the heat treatment is 150℃, and the time of the heat treatment is 80min.

[0092] Example 6

[0093] The difference from Example 1 is that the thickness t1 of the first metal layer is 2.5mm, and the R angle R1 of the first metal layer is 8mm; the thickness t2 of the second metal layer is 4mm, and the R angle R2 of the second metal layer is 30mm.

[0094] Example 7

[0095] The difference from Example 1 is that the slope angle of the slope is 30°, the slope length L1 of the slope is 15mm, and the slope height h of the slope is 5mm.

[0096] Example 8

[0097] The difference from Example 1 is that the width L2 of the convex part is 4mm, and the height D of the convex part is 1mm.

[0098] Example 9

[0099] The difference from Example 1 is that the stamping temperature of the stamping treatment is 250℃, the stamping time is 8s, and the pressure holding time is 30s.

[0100] Comparative Example 1

[0101] The difference from Example 1 is that the incoming material is not designed, and the incoming material is a plate with equal thickness.

[0102] Comparative Example 2

[0103] The difference from Example 1 is that the mold is not designed, and the lower mold of the mold is a flat structure.

[0104] Comparative Example 3

[0105] The difference from Example 1 is that the material obtained after stamping is not subjected to heat treatment.

[0106] Performance detection

[0107] Examples 1-9 and Comparative Examples 1-3 were subjected to the following related performance tests, and the results are shown in Table 1:

[0108] First R angle: using projection method, the electronic device shell prepared by Examples 1-9 and Comparative Examples 1-3 was placed in the projection area of the projector, and the light source of the projector was used to project a light bar with accurate structure on the surface of the electronic device shell. These line patterns can be used to measure and calculate the first R angle of the electronic device shell.

[0109] Straightness, average grain size deviation: the electronic device shell prepared in Examples 1-9 and Comparative Examples 1-3 was cut along the thickness direction by a wire electrical discharge machine, the cross section was the observation surface, the observation surface was ground by 200, 400, 600, 800, 1000, 1500, 2000, 3000 grit sandpaper in turn to remove the surface wire cutting marks and ensure the observation surface was flat, the observation surface was observed by a metallographic microscope after polishing, and the straightness and average grain size deviation were measured and calculated.

[0110] Intermetallic diffusion depth: the electronic device shell prepared in Examples 1-9 and Comparative Examples 1-3 was cut along the thickness direction by a wire electrical discharge machine, the interface bonding morphology of the heterogeneous metal layer was observed by a field emission scanning electron microscope, the distribution of each element near the interface was analyzed by an energy dispersive spectrometer EDS, the interface element diffusion rule and composition change rule were deduced by measuring the content of each element in the diffusion layer at the interface position, and then the intermetallic diffusion depth was obtained.

[0111] Table 1

[0112] As can be seen from Table 1, the straightness of the bonding line formed at the interface between the outer metal layer and the inner metal layer at the first R angle of the electronic device shell prepared in Examples 1-9 is significantly smaller than that of Comparative Example 1 and Comparative Example 2 under the same R angle.

[0113] Compared with Comparative Example 3 which is not subjected to heat treatment, the average grain size deviation in the outer metal layer is significantly reduced by heat treatment and controlling the parameters within a suitable range in Examples 1-9 of the present application.

[0114] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any changes or replacements within the technical scope disclosed in the present application can be easily thought by those skilled in the art, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An electronic device housing, characterized by, The electronic device shell comprises an outer metal layer (101) and an inner metal layer (102) arranged in layers, the outer metal layer (101) and the inner metal layer (102) are metal layers of different materials; the electronic device shell has at least one first R angle, the first R angle is greater than or equal to 0.1 mm; at the first R angle, the cross-section junction of the outer metal layer (101) and the inner metal layer (102) has a junction line, the straightness of the junction line is less than 0.1 mm.

2. The electronic device case of claim 1, wherein, The diffusion depth between the metals at the interface junction of the outer metal layer (101) and the inner metal layer (102) is 0.1-10 μm.

3. The electronic device case of claim 1 or 2, wherein, The average grain size deviation of the outer metal layer (101) is less than or equal to 10%.

4. The electronic device housing of any one of claims 1-3, wherein, The thickness of the outer metal layer (101) is greater than or equal to 0.2 mm.

5. The electronic device housing of any one of claims 1-4, wherein, The outer metal layer (101) comprises at least one of aluminum and its alloys, titanium and its alloys, iron and its alloys, and zirconium and its alloys; the inner metal layer (102) comprises at least one of aluminum and its alloys, copper and its alloys, zinc and its alloys, and magnesium and its alloys.

6. The electronic device housing of any one of claims 1-5, wherein, The elastic modulus of the outer metal layer (101) is greater than or equal to 70 GPa, and the elastic modulus of the outer metal layer (101) is greater than that of the inner metal layer (102).

7. The electronic device housing of any one of claims 1-6, wherein, The yield strength of the outer metal layer (101) is greater than or equal to 150 MPa, and the strength of the outer metal layer (101) is greater than that of the inner metal layer (102).

8. The electronic device housing of any one of claims 1-7, wherein, The inner metal layer (102) has a thermal conductivity greater than or equal to 100 W-m -1 ·k -1 The inner metal layer (102) has a thermal conductivity greater than the outer metal layer (101).

9. The electronic device housing of any one of claims 1-8, wherein, The density of the inner metal layer (102) is greater than or equal to 1.2 g / cm 3 The density of the inner metal layer (102) is less than the density of the outer metal layer (101).

10. The electronic device case of any one of claims 1-9, wherein, The bonding strength of the inner metal layer (102) and the outer metal layer (101) is greater than or equal to 70 MPa.

11. A method of manufacturing for manufacturing an electronic device housing (100) according to any one of claims 1-10, characterized in that, Comprise: A composite metal to be punched (10) is provided, the composite metal to be punched (10) comprises a first metal layer (1) and a second metal layer (2) arranged in layers; the first metal layer (1) is used to form the outer metal layer (101), and the second metal layer (2) is used to form the inner metal layer (102); The composite metal to be punched (10) is placed in a punching die (200) for punching treatment, and then heat treated to obtain an electronic device shell blank; The electronic device shell blank is milled to obtain an electronic device shell (100).

12. The production method according to claim 11, wherein The edge of the side of the first metal layer (1) away from the second metal layer (2) has at least one second R angle, and the second R angle satisfies: 3t1≤second R angle≤6t1; the edge of the side of the second metal layer (2) away from the first metal layer (1) has a third R angle at the corresponding position of the second R angle, and the third R angle satisfies: 7t2≤third R angle≤13t2, wherein t1 is the thickness of the first metal layer (1), and t2 is the thickness of the second metal layer (2).

13. The production method according to claim 12, wherein A slope is formed at the transition from the second R angle to the third R angle at the corresponding position of the second R angle, and the thickness gradually decreases from the second metal layer (2) to the first metal layer (1) in the direction of the slope.

14. The production method according to claim 13, wherein The slope angle of the slope is greater than or equal to 10° and less than or equal to 40°, the distance L1 from the second R-angle vertex to the third R-angle vertex of the slope is greater than or equal to 2t, and the slope height h of the slope is less than or equal to t, wherein t is the thickness of the composite metal (10) to be punched.

15. The production method according to claim 14, wherein The stamping die (200) comprises an upper die (202) and a lower die (201), the lower die (201) comprises a groove, a convex portion is arranged around the position where the inner wall bottom of the groove is connected with the side wall, the first metal layer (1) of the composite metal (10) to be punched is in contact with the groove of the lower die (201), and the convex portion comprises a horizontal boss, the width L2 of the horizontal boss is greater than or equal to t2, and the height D of the horizontal boss satisfies 1 / 4t1≤D≤t1.

16. The production method according to any one of claims 11 to 15, wherein The stamping temperature T1 of the stamping process satisfies: 1 / 4T m ≤ T1 < T m , wherein T m is the minimum value of the melting point of the outer metal layer (101) and the melting point of the inner metal layer (102); the stamping time of the stamping process is 3s-15s; and the pressure holding time of the stamping process is 30s-60s.

17. The production method according to claim 16, wherein The temperature T2 of the heat treatment is ≤ 1 / 3 T m ; the time of the heat treatment is 30 min - 120 min.

18. The production method according to any one of claims 11 to 17, wherein The milling is followed by injection molding.

19. The electronic device case of claims 1-10, wherein, The electronic device shell is used in an electronic device middle frame.

20. An electronic device, comprising: The electronic device comprises the electronic device shell (100) of any one of claims 1-10 or 19, or the electronic device shell (100) prepared by the preparation method of any one of claims 11-18.

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