Preparation method of SiC modified particle multi-mode reinforced aluminum-based composite material

Abstract

The invention belongs to the technical field of aluminum-based composite material preparation, and discloses a SiC modified particle multi-mode reinforced aluminum-based composite material preparation method which comprises the following steps: S1, carrying out surface copper plating on SiC particles through a chemical plating process to prepare surface modified SiC particles; s2, preparing flexible SiC particles; s3, mixing the surface modified SiC particles prepared in the step S1, the flexible SiC particles prepared in the step S2 and aluminum matrix powder; s4, performing cold pressing on the mixture obtained in S3; s5, carrying out vacuum hot pressed sintering on the cold pressed sample obtained in S4; s6, the blank obtained through sintering in the step S5 is extruded into a bar at the temperature of 450 DEG C; s7, the bar obtained in the step S6 is subjected to two-stage solution treatment and aging treatment; the problems that an existing composite material obtained by combining SiC particles subjected to surface modification treatment and an aluminum matrix is single in performance improvement mode and low in ductility are solved.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum-based composite material preparation, and in particular to a method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material. Background Art

[0002] Silicon carbide (SiC) particle reinforced aluminum matrix composite material refers to a composite material with silicon carbide particles as the reinforcement phase and aluminum or aluminum alloy as the matrix. It has become a hot new structural material due to its low density, low price, high specific strength and specific elastic modulus, wear resistance and corrosion resistance, good high temperature performance and processing characteristics. It has been widely used in the fields of aerospace, electronics, automobile and sports industries, such as in aircraft engine stator blades, automobile brake discs, pistons, drive rods and engine cylinders. At present, its preparation methods include powder metallurgy, extrusion casting, spray deposition, rapid solidification, stirring casting, in-situ synthesis and other methods. However, in the preparation process of various SiC particle aluminum matrix composite materials, due to the wetting and interface reaction problems between SiC reinforcement particles and matrix metal, the brittle product Al4C3 generated is often formed on the SiC surface in the form of discontinuous flakes or discs, and Al4C3 has strong water absorption and easy hydrolysis, which will lead to material performance not meeting the expected requirements.

[0003] Under the condition of certain silicon carbide content, in order to ensure the effective addition of SiC particles and improve the strengthening effect, the surface modification of SiC particles is mainly carried out to improve the interface bonding to achieve the purpose of strengthening material performance. However, the elongation of SiC particle aluminum-based composite materials prepared by only surface-modified SiC particles is low, and the practical range of the composite materials is small. Therefore, the present invention proposes a method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material to solve this problem. Summary of the invention

[0004] The present invention aims to provide a method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material to solve the problem that the performance improvement mode of the existing composite material obtained by combining surface-modified SiC particles with an aluminum matrix is ​​relatively single and the elongation is low.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material comprises the following steps:

[0007] S1, copper plating the surface of SiC particles by chemical plating process to prepare surface modified SiC particles;

[0008] S2, preparing flexible SiC particles;

[0009] S3, mixing the surface modified SiC particles prepared in S1, the flexible SiC particles prepared in S2 and the aluminum matrix powder, the mixing time is 2h;

[0010] S4, cold pressing the mixture obtained in S3, wherein the pressure is 12 MPa and the pressure holding time is 40 min;

[0011] S5, subjecting the cold pressed sample obtained in S4 to vacuum hot pressing sintering, wherein the sintering pressure is 30 MPa, the sintering temperature is 605°C, and the holding time is 50 min;

[0012] S6, extruding the blank sintered in step S5 into a rod at 450° C., with an extrusion ratio of 14:1;

[0013] S7, subjecting the rod obtained in step S6 to a two-stage solution treatment and an aging treatment.

[0014] Furthermore, in step S1, the specific method of copper plating is:

[0015] A1. Degreasing SiC particles using ethanol solution;

[0016] A2, using hydrofluoric acid to coarsen the SiC particles obtained by treatment A1;

[0017] A3, sensitizing the SiC particles obtained by treatment A2 with hydrochloric acid and stannous chloride;

[0018] A4, activating the SiC particles obtained by the treatment in A3 with silver nitrate and ammonia water;

[0019] A5. Use a plating solution at 50°C to plate the SiC particles obtained by the A4 treatment.

[0020] Furthermore, in step A5, the plating solution is a solution with a pH value of 12 prepared from copper sulfate, formaldehyde, EDTA, sodium hydroxide and sodium carbonate.

[0021] Furthermore, in step S2, the specific method for preparing the flexible particles is:

[0022] B1, preparing a composite material of an aluminum matrix based on the surface-modified SiC particles prepared in step S1 and the SiC particles without surface modification;

[0023] B2, turning the composite material prepared in B1 to obtain aluminum-based composite material chips;

[0024] B3. Grind the debris obtained in B1 into particles by ball milling to obtain flexible SiC particles.

[0025] Furthermore, in steps S3 and B1, the material of the aluminum substrate is 7075 aluminum alloy.

[0026] Beneficial effects of the technical solution:

[0027] The present invention adopts a dual reinforcement method of surface modification and flexible reinforced particles, and prepares SiC reinforced particle composite reinforced aluminum-based composite materials based on powder metallurgy, thereby overcoming the problems of low elongation and poor toughness of traditional SiC reinforced particle aluminum-based composite materials. In the powder metallurgy preparation process, surface copper-plated SiC particles and flexible SiC particles are introduced to improve the performance of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material according to the present invention;

[0029] Figure 2 Schematic diagram of the structure of SiC particles reinforced aluminum matrix composite without surface modification;

[0030] Figure 3 A schematic diagram of the structure of the SiC modified particle multi-mode reinforced aluminum-based composite material prepared by the present invention;

[0031] Figure 4 This is a schematic diagram of the SEM morphology of SiC particles before copper plating;

[0032] Figure 5 This is a schematic diagram of the SEM morphology of SiC particles after copper plating;

[0033] Figure 6 This is the metallographic image of SiC particle reinforced aluminum matrix composite without surface modification;

[0034] Figure 7 The metallographic image of the SiC modified particle multi-mode reinforced aluminum-based composite material prepared by the present invention;

[0035] Figure 8 It is a performance comparison chart of the non-surface-modified SiC particle reinforced aluminum-based composite material in Example 1 and the SiC modified particle multi-mode reinforced aluminum-based composite material prepared in the present invention. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0037] like Figures 1 to 7 As shown, a method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material comprises the following steps:

[0038] S1, copper plating the surface of SiC particles by chemical plating process to prepare surface modified SiC particles;

[0039] Preferably, the specific method of copper plating is:

[0040] A1. Degreasing SiC particles using ethanol solution;

[0041] A2, using hydrofluoric acid to coarsen the SiC particles obtained by treatment A1;

[0042] A3, sensitizing the SiC particles obtained by treatment A2 with hydrochloric acid and stannous chloride;

[0043] A4, activating the SiC particles obtained by the treatment in A3 with silver nitrate and ammonia water;

[0044] A5. Use a plating solution at 50°C to plate the SiC particles obtained by the A4 treatment.

[0045] Preferably, the plating solution is a solution with a pH value of 12 prepared from copper sulfate, formaldehyde, EDTA, sodium hydroxide and sodium carbonate.

[0046] S2, preparing flexible SiC particles;

[0047] Preferably, the specific method for preparing the flexible particles is:

[0048] B1, preparing a composite material of an aluminum matrix based on the surface-modified SiC particles prepared in step S1 and the SiC particles without surface modification;

[0049] B2, turning the composite material prepared in B1 to obtain aluminum-based composite material chips;

[0050] B3. Grind the debris obtained in B1 into particles by ball milling to obtain flexible SiC particles.

[0051] S3, mixing the surface modified SiC particles prepared in S1, the flexible SiC particles prepared in S2 and the aluminum matrix powder, the mixing time is 2h;

[0052] Preferably, the material of the aluminum substrate is 7075 aluminum alloy.

[0053] S4, cold pressing the mixture obtained in S3, wherein the pressure is 12 MPa and the pressure holding time is 40 min.

[0054] S5. The cold pressed sample obtained in S4 is subjected to vacuum hot pressing sintering, wherein the sintering pressure is 30 MPa, the sintering temperature is 605°C, and the holding time is 50 min.

[0055] S6. Extruding the blank sintered in step S5 into rods at 450° C. with an extrusion ratio of 14:1.

[0056] S7, subjecting the rod obtained in step S6 to a two-stage solid solution + aging treatment.

[0057] Example 1 (7075 aluminum alloy as aluminum matrix)

[0058] Step 1: Copper plating modification of SiC particles

[0059] The surface of SiC particles is plated with copper by chemical plating. The chemical reaction between SiC particles and aluminum matrix is ​​inhibited by plating, the formation of brittle products such as Al4C3 phase is prevented, the interface bonding strength between SiC particles and aluminum matrix is ​​strengthened, and the elongation of composite materials is improved in the later stage. Surface copper plating method: ① Degreasing SiC particles with ethanol solution; ② Roughening with hydrofluoric acid; ③ Sensitization with hydrochloric acid and stannous chloride; ④ Activation with silver nitrate and ammonia water; ⑤ Plating solution with pH value of 12 is prepared with copper sulfate, formaldehyde, EDTA, sodium hydroxide and sodium carbonate at 50℃.

[0060] Step 2: Preparation of flexible SiC particles

[0061] A composite material with the same aluminum matrix was prepared based on unsurface-modified SiC particles (conventional SiC particles) and surface-modified SiC particles. Flexible reinforced particles were prepared by turning-ball milling to achieve coordinated deformation of particles and matrix in the later composite material, which also pointed out the direction for the recycling of silicon carbide aluminum-based composite materials.

[0062] Step 3: Mix the powder

[0063] The surface modified SiC particles, the surface modified flexible SiC particles and the aluminum matrix powder are mixed for 2 hours, and the powder metallurgy method is used for material preparation.

[0064] Step 4: Cold Pressing

[0065] The prepared powder was cold pressed at a pressure of 12 MPa and a holding time of 40 min.

[0066] Step 5: Vacuum hot pressing sintering

[0067] The prepared powder cold pressed sample was subjected to vacuum hot pressing sintering with a sintering pressure of 30 MPa, a sintering temperature of 605°C and a holding time of 50 min.

[0068] Step 6: Hot Extrusion

[0069] The vacuum hot-pressed sintered sample was extruded into rods at 450°C, with an extrusion ratio of 14:1. -- Tensile test, strain rate of 1×10-3s-1, sample gauge length of 40mm, parallel section length of 44mm, diameter of 8mm, and the tensile direction was parallel to the extrusion direction.

[0070] Step 7: Solution + Aging Treatment

[0071] The heat treatment process is double-stage solution treatment + artificial aging process, such as Figure 8 As shown, after heat treatment, the tensile strength is 670MPa, the yield strength is 612MPa, and the elongation is 7.6%. Compared with before modification, the elongation is increased by 16%, which solves the problem of low elongation, and the tensile strength and yield strength are slightly improved.

[0072] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material, characterized in that: The following steps are involved: S1, copper plating the surface of SiC particles by chemical plating process to prepare surface modified SiC particles; S2, preparing flexible SiC particles; S3, mixing the surface modified SiC particles prepared in S1, the flexible SiC particles prepared in S2 and the aluminum matrix powder, the mixing time is 2h; S4, cold pressing the mixture obtained in S3, wherein the pressure is 12 MPa and the pressure holding time is 40 min; S5, subjecting the cold pressed sample obtained in S4 to vacuum hot pressing sintering, wherein the sintering pressure is 30 MPa, the sintering temperature is 605°C, and the holding time is 50 min; S6, extruding the blank sintered in step S5 into a rod at 450° C., with an extrusion ratio of 14:1; S7, subjecting the rod obtained in step S6 to a two-stage solution treatment and an aging treatment.

2. The method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material according to claim 1, characterized in that: In step S1, the specific method of copper plating is: A1. Degreasing SiC particles using ethanol solution; A2, using hydrofluoric acid to coarsen the SiC particles obtained by treatment A1; A3, sensitizing the SiC particles obtained by treatment A2 with hydrochloric acid and stannous chloride; A4, activating the SiC particles obtained by the treatment in A3 with silver nitrate and ammonia water; A5. Use a plating solution at 50°C to plate the SiC particles obtained by the A4 treatment.

3. The method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material according to claim 2, characterized in that: In step A5, the plating solution is a solution with a pH value of 12 prepared from copper sulfate, formaldehyde, EDTA, sodium hydroxide and sodium carbonate.

4. The method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material according to claim 1, characterized in that: In step S2, the specific method for preparing the flexible particles is: B1, preparing a composite material of an aluminum matrix based on the surface-modified SiC particles prepared in step S1 and the SiC particles without surface modification; B2, turning the composite material prepared in B1 to obtain aluminum-based composite material chips; B3. Grind the debris obtained in B1 into particles by ball milling to obtain flexible SiC particles.

5. The method for preparing a SiC modified particle multi-mode reinforced aluminum-based composite material according to claim 4, characterized in that: In steps S3 and B1, the material of the aluminum substrate is 7075 aluminum alloy.

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