A method for preparing metal matrix composites by friction stir processing and applications thereof

Abstract

The present application relates to a kind of metal matrix composite prepared by friction stir processing method, including the mixing of metal matrix composite reinforcement and substrate powder, according to the size of stir pin and shaft shoulder in the stir head of friction stir equipment, using milling cutter to open the groove on pure metal mold, the width is greater than the diameter of stir pin, the depth is greater than the length of stir pin;Reinforcement and substrate powder mixture is added to the groove and is maximized compaction, in the processing area of special friction stir welding machine, the center of stir pin of stir head is aligned with the center of groove, is prepared under the processing scheme of multiple passes variable stir head speed, obtains metal matrix composite at the groove of composite plate processing area, the obtained metal matrix composite reinforcement is uniformly distributed, and the mechanical and friction and wear performance is excellent.The present application can automatically prepare a variety of different kinds of metal matrix composite, without determining specific process parameters for different kinds of metal and reinforcement test, and is widely applicable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal matrix composite material preparation, in particular to a method for preparing metal matrix composite material by using friction stir processing technology with a groove width greater than the diameter of a stirring pin and application thereof. BACKGROUND

[0002] Metal matrix composite materials can have mechanical properties such as light weight, high strength and large stiffness, and are widely used in aerospace, automobile manufacturing, electronics and power, biopharmaceuticals, sports and other industries. Metal matrix is usually aluminum, magnesium, copper and their alloys, and also includes high-entropy alloys and titanium alloys with very high melting points. The friction stir processing technology, which has the characteristics of solid-phase processing, has been developed for some time. The existing friction stir processing technology applied to the preparation of metal matrix composite materials has two characteristics. First, the metal plate is used as the base material, i.e., the metal plate is the metal matrix. Second, holes or grooves are made in the metal plate (the hole diameter or groove width is much smaller than the diameter of the stirring pin, and the hole or groove depth is much smaller than the length of the stirring pin), and only the reinforcing body is added in the hole or groove. The reinforcing body is mixed into the metal plate by friction stir processing to form a metal matrix composite material. In particular, the existing friction stir processing preparation method is not mature enough for different types of metal matrix composite materials. When facing different types of metal matrix composite materials, the friction stir processing preparation method needs to be determined by trial every time, which limits the application range of the existing friction stir processing technology in the preparation of metal matrix composite materials. Therefore, the present application aims to improve the existing friction stir processing technology and develop a preparation method for multiple types of metal matrix composite materials with wider application range and more convenient application, and expand its application range. SUMMARY

[0003] To solve the above technical problems, the present application provides a method for preparing metal matrix composite material by using friction stir processing, comprising the following steps:

[0004] (1) mixing the reinforcing body of the metal matrix composite material with the base material powder to achieve macroscopic uniform mixing of the reinforcing body in the base material powder and tight combination of the reinforcing body and the base material powder; the particle size of the reinforcing body and the base material powder is less than or equal to 100 microns;

[0005] (2) According to the size of the stir pin and the shoulder of the stir head of the friction stir equipment, a groove with a width greater than the diameter of the stir pin and a depth greater than the length of the stir pin is milled on a pure metal mold using a milling cutter; the reinforcing body and the base material powder mixture are added to the groove and compacted to the maximum extent, and then a cover plate made of the same pure metal as the mold is placed on the groove, and the two constitute a composite plate structure; the mold material is selected to be the same as the base material of the prepared metal matrix composite; the cover plate is mainly used to prevent the reinforcing body and the base material powder from overflowing during the friction stir processing; during processing, the cover plate is pressed on the surface of the mold using a clamp;

[0006] (3) In the processing area of the special friction stir welding machine, the center of the stir pin of the stir head is aligned with the center of the groove, the stir pin penetrates the cover plate, and the composite plate is prepared under a multi-pass variable stir head rotation speed processing scheme, and a metal matrix composite is obtained at the groove of the composite plate processing area, the reinforcing body of the obtained metal matrix composite is uniformly distributed, and the mechanical and friction and wear properties are excellent.

[0007] The uniform and close mixing process of the reinforcing body and the base material powder is completed by a variable speed ball milling process, the reinforcing body and the base material powder are uniformly mixed and bonded by low speed ball milling first, and the low speed ball milling process window is: ball milling speed 100-200 rpm, ball milling time greater than 4 hours; then the powders are tightly combined by high speed ball milling, and the high speed ball milling process window is: ball milling speed greater than 200 rpm, ball milling time less than 4 hours.

[0008] The uniform and close mixing method of the reinforcing body and the base material powder is not limited to variable speed ball milling, and other processes such as a mixer mixing, magnetic stirring, etc. can also be used, as long as the reinforcing body and the base material powder can be uniformly mixed and tightly combined.

[0009] Different stir heads are used according to different materials of the reinforcing body, including but not limited to: when the reinforcing body is silicon carbide, a tungsten steel stir head is used, and the prepared silicon carbide metal matrix composite has fine and dense structure and excellent performance.

[0010] The construction steps of the composite plate structure are as follows:

[0011] 1) Determine the mold plate size and the groove size according to the size of the stir head. In the present application, the mold thickness is greater than the length of the stir pin by 1.5 mm or more, the mold width is three times or more than the diameter of the stir head shoulder, and the mold length is not less than 100 mm; the width of the groove is 1-3 mm greater than the diameter of the stir pin, and the depth of the groove is 0.5 mm or more greater than the length of the stir pin;

[0012] 2) According to the mold plate size determined in step 1), a groove is obtained on the plate by using a numerical control milling machine; the burrs in the groove are removed, and the surface roughness is not less than Ra6.3;

[0013] 3) Add mixed powder in the groove, compact into a block, as shown in Figure 15 After compaction, a cover plate with the same material as the mold plate and a thickness of 2-3 mm is placed thereon to form a composite plate structure, the length and width of the cover plate being the same as those of the mold plate.

[0014] The mixed powder compaction method can use hand compaction in the experimental stage and intelligent automatic compaction technology such as mechanical vibration in the batch production stage.

[0015] The stirring head morphology is preferably smooth cylinder near the shaft shoulder to avoid splashing of mixed powder during processing.

[0016] The multi-pass variable stirring head rotation speed processing scheme at least includes a high stirring head rotation speed pass process and a low stirring head rotation speed pass process; the high stirring head rotation speed pass process window is that the stirring head rotation speed is greater than or equal to 2000 rpm, the processing speed is 40-200 mm / min, the stirring head inclination angle is 2°-3°, and the downward pressure amount is 0.2-0.8 mm; the low stirring head rotation speed pass process window is that the stirring head rotation speed is 800-1200 rpm, the processing speed is 40-200 mm / min, the stirring head inclination angle is 2°-3°, and the downward pressure amount is 0.2-0.8 mm. The specific processing pass is determined by the stirring head material and the metal base type, a high stirring head rotation speed pass process is first used to make the powder bond and form, after one pass processing, whether a high stirring head rotation speed pass process is added is determined according to whether there are macroscopic defects at the spoon hole, if there are macroscopic defects, a high stirring head rotation speed pass process is added, as shown in Fig. Figure 16 If there are no macroscopic defects, a low stirring head rotation speed pass process is used to refine the microstructure. Generally, when the stirring head material is hot work die steel, 3 passes of processing can successfully prepare silicon carbide / graphene aluminum base, magnesium base and other light alloy metal matrix composites, including 2 passes of high stirring head rotation speed pass process and 1 pass of low stirring head rotation speed pass process.

[0017] The method for preparing metal matrix composites by using friction stir processing provided by the application is used for preparing pure metal matrix composites, alloy metal matrix composites, composites mixed with pure metal matrix and reinforcing bodies, or high melting point metal matrix composites; the pure metal matrix includes but is not limited to aluminum, magnesium and copper; the reinforcing body includes but is not limited to silicon carbide or graphene; the high melting point metal includes but is not limited to high-entropy alloy and titanium alloy, and when used for preparing high melting point metal matrix composites, the stirring head adopts a material capable of bearing a high temperature of 1500℃ or above.

[0018] The beneficial effects of the application are as follows:

[0019] The present invention discloses a method for preparing metal matrix composites using friction stir processing, which can automatically prepare various types of metal matrix composites without requiring specific process parameters for different metals and reinforcements, thus having a wide range of applications. The preparation process does not generate dust or other process pollution, making it green, environmentally friendly, and low-carbon. The reinforcement content is continuously controllable, allowing the preparation of metal matrix composites with continuous proportional mass fractions of reinforcement, such as metal matrix composites containing 0-50% mass fraction of reinforcement. The resulting metal matrix composites have grain sizes down to the nanometer scale (less than 1000 nanometers), and the particle reinforcement can be refined to a size of 1 / 5 to 1 / 10 of the original particle reinforcement size. Compared with conventional friction stir processing technology, the present invention has the following characteristics: 1. The metal sheet is not the substrate but the mold, and its type does not need to be specifically specified. The purpose of the groove size being much larger than the stirring pin is to prevent the mold material from being mixed into the prepared metal matrix composite material; 2. Both the reinforcement and the metal substrate are powders. Before friction stir processing, the powders can be mixed using processes such as high-energy ball milling to achieve a more uniform and tighter bonding between the reinforcement and the metal substrate. This is beneficial for a more uniform distribution of the reinforcement and a tighter bond with the metal matrix in the prepared metal matrix composite material after friction stir processing; 3. The shape and size design of the stirring pin are relatively novel. There are no threads in the part that contacts the cover plate, and the diameter and length of the stirring pin are the limits that the stirring head can withstand; 4. In the solid state, the reinforcement and the metal matrix powder are bonded and formed into a block shape. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the processing of the metal matrix composite material prepared according to the present invention;

[0021] Figure 2 The image shows the macroscopic morphology of the silicon carbide / graphene aluminum-based composite material obtained in this invention.

[0022] Figure 3 This is a schematic diagram of the grain structure of an 8-micron silicon carbide aluminum-based composite material with a content of 20% obtained in Example 1 of the present invention;

[0023] Figure 4 This is a schematic diagram of the grain structure of the graphene-aluminum matrix composite material with a content of 1% obtained in Example 2 of the present invention;

[0024] Figure 5 This is a schematic diagram of the grain structure of the aluminum-based composite material with a content of 100% pure aluminum powder obtained in Example 3 of the present invention;

[0025] Figure 6 This is a schematic diagram of the grain structure of 1060-H16 aluminum alloy obtained in Example 4 of the present invention;

[0026] Figure 7Fracture morphology schematic diagram of 8 micron silicon carbide aluminum matrix composite material with content of 20% obtained by the embodiment 1 of the present application;

[0027] Figure 8 Fracture morphology schematic diagram of graphene aluminum matrix composite material with content of 1% obtained by the embodiment 2 of the present application;

[0028] Figure 9 Fracture morphology schematic diagram of pure aluminum powder aluminum matrix composite material with content of 100% obtained by the embodiment 3 of the present application;

[0029] Figure 10 Fracture morphology schematic diagram of 1060-H16 aluminum alloy obtained by the embodiment 4 of the present application;

[0030] Figure 11 Wear morphology schematic diagram of 8 micron silicon carbide aluminum matrix composite material with content of 20% obtained by the embodiment 1 of the present application;

[0031] Figure 12 Wear morphology schematic diagram of graphene aluminum matrix composite material with content of 1% obtained by the embodiment 2 of the present application;

[0032] Figure 13 Wear morphology schematic diagram of pure aluminum powder aluminum matrix composite material with content of 100% obtained by the embodiment 3 of the present application;

[0033] Figure 14 Wear morphology schematic diagram of 1060-H16 aluminum alloy obtained by the embodiment 4 of the present application;

[0034] Figure 15 Schematic diagram of mixed powder compaction of the present application;

[0035] Figure 16 Macroscopic schematic diagram of the metal matrix composite material prepared by the present application, wherein a, b and c are macroscopic morphology schematic diagrams determined by different reinforcing body aluminum matrix composite material processing passes. DETAILED DESCRIPTION

[0036] Referring to Figures 1-16 as shown in the drawings:

[0037] Embodiment 1,

[0038] The 8 micron silicon carbide aluminum matrix composite material with mass fraction of 20% prepared by the method of the present application comprises the following steps:

[0039] (1) The silicon carbide reinforcement of the metal matrix composite material was mixed with pure aluminum powder as the base material. A QM-3SP4 planetary ball mill was used with a 100 ml agate ball mill jar, zirconia balls with diameters of 3 mm and 6 mm, a ball-to-material ratio of 8:1, and a ball-to-size ratio of 3:1. Under the condition of room temperature without isolation from air, the ball mill was first ball-milled at low speed with the following parameters: ball milling speed 120 r / min and ball milling time 6 h. After the low-speed ball milling, the ball milling was stopped for 12 h to cool down, and then ball milling was carried out at high speed with the following parameters: ball milling speed 250 r / min and ball milling time 2 h. The mixing of silicon carbide and pure aluminum was completed, achieving macroscopic uniform mixing of the reinforcement in the base material powder and tight bonding between the reinforcement and the base material powder, with the base material and reinforcement mutually encapsulating each other. The particle size of pure aluminum powder was about 5 micrometers, and the particle size of silicon carbide was about 8 micrometers.

[0040] (2) In this embodiment, a hot-work die steel stirring head is used. Its specific dimensions are: a right-hand threaded cylindrical stirring pin with a length of 5.8 mm and a diameter of 7 mm; a grooved shoulder with a diameter of 17 mm; and die plate dimensions of: length x width x height = 100 mm x 70 mm x 8 mm. Based on the dimensions of the stirring pin and shoulder in the stirring head, a groove with a width greater than the diameter of the stirring pin and a depth greater than the length of the stirring pin is cut into the pure metal die using a milling cutter. The groove dimensions are: length x width x depth = 60 mm x 8 mm x 6.5 mm (e.g., ...). Figure 1 Remove burrs from the groove, and the surface roughness shall not be less than Ra6.3; add the mixture of reinforcement and base material powder into the groove and compact it to the maximum extent, and then cover the groove with a pure metal cover plate of the same material as the mold. The cover plate has the following dimensions: length x width x height = 100mm x 70mm x 2mm. The two together form a composite plate structure; the mold and cover plate are made of 1060 aluminum.

[0041] (3) In the processing area of ​​the HWI-JBH-T special friction stir welding machine, the stirring needle center of the stirring head is aligned with the center of the groove and the material is prepared under a multi-pass variable stirring head speed processing scheme. The processing passes are 3. The stirring head speed of the first two passes is 2300 rpm, the processing speed is 40 mm / min, the stirring head tilt angle is 2.5°, and the downward pressure is 0.4 mm. The stirring head speed of the third pass is 1200 rpm, the processing speed is 40 mm / min, the stirring head tilt angle is 2.5°, and the downward pressure is 0.4 mm. 20% 8-micron silicon carbide aluminum-based composite material with a content of 20% is obtained in the groove of the composite plate processing area. The resulting metal matrix composite material reinforcement is uniformly distributed and has excellent mechanical and tribological properties.

[0042] Example 2

[0043] A graphene-aluminum-based composite material with a mass fraction of 1% was prepared using the method of the present invention. The preparation steps were the same as in Example 1, wherein the diameter of the reinforcing graphene sheet was 1-3 micrometers and the thickness was 1-5 nanometers; a graphene-aluminum-based composite material with a content of 1% was obtained in the groove of the processing area of ​​the composite board.

[0044] Example 3

[0045] A pure aluminum powder aluminum-based composite material with a mass fraction of 100% was prepared using the method of the present invention. The preparation steps were the same as in Example 1, except that the raw material consisted only of pure aluminum powder with a particle size of about 5 micrometers. A pure aluminum powder aluminum-based composite material with a content of 100% was obtained in the groove of the processing area of ​​the composite plate.

[0046] Example 4

[0047] The method of this invention was used to prepare an aluminum-based composite material with a mass fraction of 100% pure aluminum powder. The preparation steps were the same as in Example 1, except that the raw material consisted only of pure aluminum powder with a particle size of about 5 micrometers; the mold was made of 1060-H16 aluminum alloy.

[0048] Comparative examples of the metal matrix composites obtained in Examples 1-4:

[0049] like Figures 3-4 As shown, microstructure analysis reveals that both the 20% silicon carbide aluminum-based composite material (8 μm) and the 1% graphene aluminum-based composite material exhibit significantly refined microstructures, displaying equiaxed, uniformly distributed fine grains with nanometer-scale grain sizes of 8 nm and 4 nm, respectively. Among these, [the following information is missing from the original text]. Figure 3 Uniform distribution of black silicon carbide particles was clearly observed, with no agglomeration, and the size was refined to the nanometer scale. Tensile tests at room temperature showed that the tensile strengths of the 20% silicon carbide aluminum-based composite material and the 1% graphene aluminum-based composite material were 147 MPa and 121.1 MPa, respectively; the elongations were 8% and 55.6%, respectively; and the fracture mechanisms were cleavage fracture and plastic fracture, respectively. Microhardness tests at room temperature showed that the microhardness at the center of the processed area of ​​the 20% silicon carbide aluminum-based composite material and the 1% graphene aluminum-based composite material were 126 HV and 68 HV, respectively. Tribological wear tests at room temperature showed that the main wear mechanisms of the 20% silicon carbide aluminum-based composite material and the 1% graphene aluminum-based composite material were adhesive wear and abrasive wear, respectively.

[0050] like Figure 5As shown, microstructure analysis reveals that the aluminum-based composite material with 100% pure aluminum powder exhibits significantly refined microstructure, displaying equiaxed, uniformly distributed fine grains, all within the nanometer range (80 nm). Tensile testing at room temperature indicates that the aluminum-based composite material with 100% pure aluminum powder has a tensile strength of 107 MPa and an elongation of 47%, with plastic fracture as the fracture mechanism. Microhardness testing at room temperature shows that the microhardness at the center of the processed area of ​​the aluminum-based composite material with 100% pure aluminum powder is 48 HV. Friction and wear testing at room temperature indicates that the primary wear mechanism of the aluminum-based composite material with 100% pure aluminum powder is oxidative wear.

[0051] like Figure 6 As shown, microstructure analysis reveals that the 1060-H16 aluminum alloy has a slender microstructure with a unidirectional grain size of 8 micrometers. Tensile testing at room temperature indicates that the 1060-H16 aluminum alloy has a tensile strength of 90 MPa, an elongation of 42%, and exhibits ductile fracture as the fracture mechanism. Microhardness testing at room temperature shows that the 1060-H16 aluminum alloy has a microhardness of 30 HV. Friction and wear testing at room temperature indicates that the primary wear mechanism of the 1060-H16 aluminum alloy is delamination wear.

[0052] By comparing Examples 1-4, it can be found that the new process developed in this invention can successfully process both pure metal powder and mixed powders of reinforcement and pure metal powder. The microstructure is refined in all cases. The differences in tensile properties, microhardness, and wear mechanisms between the 100% pure aluminum powder aluminum matrix composite, the 20% 8-micron silicon carbide aluminum matrix composite, and the 1% graphene aluminum matrix composite are mainly caused by the content and type of reinforcement. However, by comparing the microstructure, tensile properties, microhardness, and wear mechanisms among Examples 1-4, it can be found that the 100% pure aluminum powder aluminum matrix composite, the 20% 8-micron silicon carbide aluminum matrix composite, and the 1% graphene aluminum matrix composite all have advantages over 1060-H16 aluminum alloy. This sufficiently demonstrates the superiority of the new process developed in this invention for preparing metal matrix composites using friction stirring with a groove width greater than the diameter of the stirring pin.

Claims

1. A method for producing a metal matrix composite material by means of friction stir processing, characterized by: It comprises the following steps: (1) mixing the reinforcing body of the metal matrix composite with the substrate powder to achieve macro-uniform mixing of the reinforcing body in the substrate powder and tight bonding effect of the reinforcing body and the substrate powder; the particle size of the reinforcing body and the substrate powder is less than or equal to 100 microns; the mixing process of the reinforcing body and the substrate powder is completed by a variable speed ball milling process, the reinforcing body and the substrate powder are uniformly mixed and bonded with each other by low speed ball milling, and the low speed ball milling process window is: ball milling speed 100-200 rpm, ball milling time greater than 4 hours; then the powders are tightly bonded by high speed ball milling, and the high speed ball milling process window is: ball milling speed greater than 200 rpm, ball milling time less than 4 hours; (2) according to the size of the stirring pin and the shaft shoulder in the stirring head of the friction stir equipment, a groove with a width greater than the diameter of the stirring pin and a depth greater than the length of the stirring pin is opened on a pure metal mold using a milling cutter; the material of the mold is the same as that of the substrate of the prepared metal matrix composite; the reinforcing body and the substrate powder mixture is added to the groove and compacted to the maximum extent, and then a pure metal cover plate with the same material as the mold is placed on the groove, and the two constitute a composite plate structure; the construction steps of the composite plate are as follows: 1) according to the size of the stirring head, the size of the mold plate and the size of the groove are determined, the thickness of the mold is greater than the length of the stirring pin by 1.5 mm or more, the width of the mold is three times the diameter of the shaft shoulder of the stirring head or more, and the length of the mold is not less than 100 mm; the width of the groove is 1-3 mm greater than the diameter of the stirring pin, and the depth of the groove is 0.5 mm or more greater than the length of the stirring pin; 2) according to the size of the mold plate determined in step 1), a groove is obtained on the plate by using a numerical control milling machine; the burrs in the groove are removed, and the surface roughness is not less than Ra6.3; 3) add mixed powder in the groove, compact it, and then place a cover plate with a thickness of 2-3 mm made of the same material as the mold plate on it to form a composite plate structure, and the length and width of the cover plate are the same as those of the mold plate; (3) in the processing area of the special friction stir welding machine, the center of the stirring pin of the stirring head is aligned with the center of the groove, and the metal matrix composite is prepared under a multi-pass variable stirring head speed processing scheme; the metal matrix composite is obtained at the groove in the processing area of the composite plate; the multi-pass variable stirring head speed processing scheme at least includes a high stirring head speed pass process and a low stirring head speed pass process; the high stirring head speed pass process window is: stirring head speed greater than or equal to 2000 rpm, processing speed 40-200 mm / min, stirring head inclination angle 2°-3°, and downward pressure 0.2-0.8 mm; the low stirring head speed pass process window is: stirring head speed 800-1200 rpm, processing speed 40-200 mm / min, stirring head inclination angle 2°-3°, and downward pressure 0.2-0.8 mm.

2. The method for manufacturing a metal matrix composite material by friction stir processing according to claim 1, characterized by: The stirring head morphology is smooth and cylindrical near the shaft shoulder.

3. A method for producing a metal matrix composite material by friction stir processing, characterized by: The preparation of 8 micron silicon carbide aluminum matrix composite with a mass fraction of 20% or graphene aluminum matrix composite with a mass fraction of 1% comprises the following steps: (1) The reinforcing body silicon carbide or graphene of the metal matrix composite material is mixed with the base material powder pure aluminum powder, a QM-3SP4 planetary ball mill, a 100-ml agate ball mill tank, zirconia balls with a diameter of 3 mm and 6 mm, a ball-to-material ratio of 8:1, and a large ball-to-small ball ratio of 3:1; under the condition of no air isolation at room temperature, the low-speed ball milling parameters are as follows: ball milling speed 120 r / min, ball milling time 6 h; after low-speed ball milling, the temperature is lowered after stopping for 12 h, and then high-speed ball milling is carried out, the parameters are as follows: ball milling speed 250 r / min, ball milling time 2 h, the mixing of silicon carbide and pure aluminum is completed, the macro-uniform mixing of the reinforcing body in the base material powder and the close combination effect of the reinforcing body and the base material powder are achieved, and the base material and the reinforcing body are wrapped around each other; the particle size of the pure aluminum powder is 5 microns, the particle size of the silicon carbide is 8 microns, the flake diameter of the graphene is 1-3 microns, and the thickness is 1-5 nanometers; (2) A hot work die steel material stirring head is used, and the specific size is as follows: the length of the right-handed threaded cylindrical stirring needle is 5.8 mm, the diameter is 7 mm, and the groove-shaped shaft shoulder diameter is 17 mm; the size of the die plate is: length X width X height = 100 mm X 70 mm X 8 mm; according to the size of the stirring needle and the shaft shoulder in the stirring head, a groove with a width greater than the diameter of the stirring needle and a depth greater than the length of the stirring needle is opened on the pure metal die by using a milling cutter, and the size of the groove is: length X width X depth = 60 mm X 8 mm X 6.5 mm; burrs in the groove are removed, and the surface roughness is not less than Ra6.3; the reinforcing body and the base material powder mixture are added to the groove and compacted to the maximum extent, and then a pure metal cover plate with the same material as the die is placed on the groove, and the size of the cover plate is: length X width X height = 100 mm X 70 mm X 2 mm, and the two form a composite plate structure; (3) In the processing area of the special friction stir welding machine, the center of the stirring needle of the stirring head is aligned with the center of the groove, and is prepared under a multi-pass variable stirring head speed processing scheme, the processing passes are 3, the stirring head speed of the first two passes is 2300 r / min, the processing speed is 40 mm / min, the stirring head inclination angle is 2.5°, and the pressing amount is 0.4 mm; the stirring head speed of the third pass is 1200 r / min, the processing speed is 40 mm / min, the stirring head inclination angle is 2.5°, and the pressing amount is 0.4 mm; 8-micron silicon carbide aluminum matrix composite material with a content of 20% or graphene aluminum matrix composite material with a mass fraction of 1% is obtained at the groove of the composite plate processing area.

Images