阅读说明：本技术 高强碳化硅颗粒增强铝基复合材料的方法及其复合材料 (Method for reinforcing aluminium base composite material by high-strength silicon carbide particle and composite material thereof ) 是由 崔铖 于 2020-07-16 设计创作，主要内容包括：本发明公开了一种高强碳化硅颗粒增强铝基复合材料的方法及其复合材料,包括以下步骤：S1、将不同粒径的碳化硅颗粒以及铝粉按照一定的质量比球磨均匀；S2、加入粘合剂、乳蜡和磷酸二氢铝,搅拌均匀并过筛备用；S3、将过筛后的物料放入模具当中,脱模后得到碳化硅铝预烧体；S4、将预烧体进行烧结、粉碎、球磨整形,过筛,得到碳化硅铝颗粒等步骤。本发明通过对小粒径碳化硅颗粒进行改性处理后,再制得碳化硅铝预制型,最后进行差压浸渗铝液,得到高强度碳化硅增强铝复合材料,该方法解决了亚微米或纳米级的碳化硅铝(颗粒尺寸小于1μm)存在的易团聚、难浸渗的缺陷,克服了现有压力铸造和搅拌铸造所存在的不足。(The invention discloses a method for preparing a high-strength silicon carbide particle reinforced aluminum matrix composite and the composite, which comprises the following steps: s1, uniformly ball-milling silicon carbide particles with different particle sizes and aluminum powder according to a certain mass ratio; s2, adding the adhesive, the milk wax and the aluminum dihydrogen phosphate, stirring uniformly and sieving for later use; s3, placing the sieved material into a mold, and demolding to obtain a silicon aluminum carbide pre-sintered body; and S4, sintering, crushing, ball-milling and shaping the pre-sintered body, and sieving to obtain silicon aluminum carbide particles. The invention obtains the high-strength silicon carbide reinforced aluminum composite material by modifying small-particle-size silicon carbide particles, then preparing a silicon aluminum carbide prefabricated model and finally infiltrating aluminum liquid in a differential pressure manner.)

1. A method for reinforcing an aluminum matrix composite by high-strength silicon carbide particles is characterized by comprising the following steps:

s1, uniformly ball-milling silicon carbide particles with the particle sizes of 0.1-0.25 mu m, 0.3-0.5 mu m and 0.6-0.8 mu m and aluminum powder with the particle size of 5-10 mu m in an inert gas atmosphere according to a certain mass ratio;

s2, adding 0.5-3% of adhesive, 0.5-2% of emulsion wax and 0.3-1% of aluminum dihydrogen phosphate into the ball-milled materials, uniformly stirring and sieving for later use;

s3, placing the sieved material into a mold, maintaining the pressure for 5-60S under the pressure of 10-20 MPa, and demolding to obtain a silicon aluminum carbide pre-sintered body;

s4, sintering the pre-sintered body in a vacuum weak reducing atmosphere sintering furnace to obtain the silicon aluminum carbide material with low aluminum content after sintering;

s5, crushing, ball-milling and shaping the silicon aluminum carbide composite material, and sieving to obtain silicon aluminum carbide particles;

and S6, taking the silicon aluminum carbide particles obtained in the step S5 as the raw material of the high-strength silicon carbide particle reinforced aluminum matrix composite.

2. The method of claim 1, wherein the silicon carbide particles with particle diameters of 0.1-0.25 μm, 0.3-0.5 μm, 0.6-0.8 μm, and the aluminum powder with particle diameters of 5-10 μm are present in a mass ratio of 5-25: 10-35: 30-75: 5-10.

3. the method of claim 2, wherein the silicon carbide particles have a particle size of 0.25 μm, 0.5 μm, and 0.8 μm in S1.

4. The method of claim 1, wherein the sintering temperature is 500-800 ℃ and the sintering atmosphere is a mixture of nitrogen and hydrogen at S4.

5. The method of claim 1, wherein the binder is selected from one or more of polyvinyl alcohol, polyvinyl acetate, dextrin, and paraffin wax.

6. The preparation method of the high-strength silicon aluminum carbide composite material is characterized by comprising the following steps of:

s5.1, selecting the silicon aluminum carbide particles prepared by the method for preparing the high-strength silicon carbide particle reinforced aluminum matrix composite material according to any one of claims 1 to 5, and respectively selecting the silicon aluminum carbide particles with the particle sizes of 8 to 12 microns, 20 to 40 microns and 50 to 80 microns;

s5.2, uniformly mixing silicon aluminum carbide particles with the particle sizes of 8-12 microns, 20-40 microns and 50-80 microns according to a certain mass ratio, then adding 0.5-3% of adhesive, 0.5-2% of emulsion wax and 0.5-5% of pore-forming agent by mass ratio, uniformly stirring and sieving for later use;

s5.3, putting the material prepared in the previous step into a die to prepare a pre-sintered body;

s5.4, sintering the pre-sintered body in a vacuum weak reducing atmosphere sintering furnace to obtain a silicon-aluminum carbide prefabricated model;

s5.5, placing the silicon aluminum carbide prefabricated model into a mold in a vacuum differential pressure casting furnace, and injecting an aluminum alloy metal liquid into pores of the silicon aluminum carbide prefabricated model by a vacuum differential pressure casting method to prepare a composite material;

and S5.6, after cooling, putting the composite material into a heat treatment furnace for annealing treatment, thus obtaining the high-strength aluminum-based silicon carbide composite material.

7. The method for preparing a high-strength silicon aluminum carbide composite material according to claim 6, wherein the mass ratio of silicon aluminum carbide particles with the particle diameters of 8-12 μm, 20-40 μm and 50-80 μm is 10-20: 20-40: 30-70.

8. the method for preparing a high-strength silicon aluminum carbide composite material according to claim 6, wherein the silicon aluminum carbide particles with the particle diameters of 10 μm, 30 μm and 60 μm are mixed in a mass ratio of 10-20: 20-40: 30-70, then adding adhesive, emulsion wax and pore-forming agent.

9. The method for preparing the high-strength silicon aluminum carbide composite material according to claim 6, wherein the binder is selected from one or more of polyvinyl alcohol, polyvinyl acetate, dextrin and paraffin wax; the pore-forming agent is selected from one or more of starch, carbon powder and ammonium oxalate.

10. A high-strength silicon aluminum carbide composite material, characterized in that the high-strength silicon aluminum carbide composite material is prepared by the method for preparing a high-strength silicon aluminum carbide composite material according to any one of claims 5 to 9, the bending strength of the high-strength silicon aluminum carbide composite material is not less than 600MPa, and the air tightness is less than 10^－10Pa·m³/s。

Technical Field

The invention relates to the technical field of composite material preparation, in particular to a method for preparing a high-strength silicon carbide particle reinforced aluminum matrix composite material and the composite material.

Background

The silicon-aluminum carbide composite material belongs to a ceramic reinforced metal matrix composite material, and takes aluminum alloy as a matrix and silicon carbide ceramic particles as a reinforcing phase. The composite material has the advantages of high specific stiffness, high thermal conductivity, low expansion coefficient, low density and the like, and is widely applied to the fields of aerospace, high-power electronic component heat dissipation packaging, optical devices, wear resistance and the like.

The existing high-volume silicon carbide aluminum composite material is obtained by adopting a pressure casting mode, namely, silicon carbide particles are firstly adopted to prepare a porous ceramic prefabricated model, then an aluminum alloy solution permeates into silicon carbide ceramic through pressure casting, the method has no problem for preparing the silicon carbide aluminum material with common strength, and is difficult to prepare the ultrahigh-strength composite material, especially when the size of the silicon carbide particles is less than 5 mu m, the silicon carbide particles in the sintering or heating process of the prepared ceramic prefabricated model can move or diffuse, reserved channels are extruded, and therefore the aluminum liquid can not permeate into the silicon carbide prefabricated model, or even if a small amount of silicon carbide particles permeate into the surface layer, the performance can not meet the requirements far.

When the size of silicon carbide particles is less than 5 mu m, the submicron or nanoscale silicon aluminum carbide is mostly realized by adopting a stirring casting method, however, the method is easy to generate particle agglomeration, the volume fraction of the prepared composite material is generally difficult to be more than 25%, and the strength and the performance in all aspects are not as good as those of a product prepared by a pressure casting method.

Disclosure of Invention

The invention aims to: aiming at the existing problems, the method for enhancing the aluminum matrix composite by the high-strength silicon carbide particles and the composite thereof are provided, the high-strength silicon carbide particle composite is obtained by modifying the small-particle size silicon carbide particles, then obtaining the silicon carbide aluminum prefabricated model, and finally infiltrating aluminum liquid by differential pressure, so that the problem that the high-volume small-particle size silicon carbide prefabricated model cannot infiltrate the aluminum liquid is solved, a new thought is provided for the preparation of the high-strength silicon carbide particle composite, and the defects of the existing pressure casting and stirring casting are overcome.

The technical scheme adopted by the invention is as follows: a method for reinforcing an aluminum matrix composite by high-strength silicon carbide particles is characterized by comprising the following steps:

s1, uniformly ball-milling silicon carbide particles with the particle sizes of 0.1-0.25 mu m, 0.3-0.5 mu m and 0.6-0.8 mu m and aluminum powder with the particle size of 5-10 mu m in an inert gas atmosphere according to a certain mass ratio;

s2, adding 0.5-3% of adhesive, 0.5-2% of emulsion wax and 0.3-1% of aluminum dihydrogen phosphate into the ball-milled materials, uniformly stirring and sieving for later use;

s3, placing the sieved material into a mold, maintaining the pressure for 5-60S under the pressure of 10-20 MPa, and demolding to obtain a silicon aluminum carbide pre-sintered body;

s4, sintering the pre-sintered body in a vacuum weak reducing atmosphere sintering furnace to obtain the silicon aluminum carbide material with low aluminum content after sintering;

s5, crushing, ball-milling and shaping the silicon aluminum carbide composite material, and sieving to obtain silicon aluminum carbide particles;

and S6, taking the silicon aluminum carbide particles obtained in the step S5 as the raw material of the high-strength silicon carbide particle reinforced aluminum matrix composite.

In the present invention, the mass ratio of silicon carbide particles having particle diameters of 0.1 to 0.25. mu.m, 0.3 to 0.5. mu.m, and 0.6 to 0.8. mu.m to aluminum powder having particle diameters of 5 to 10 μm is 5 to 25: 10-35: 30-75: 5-10.

preferably, in S1, the silicon carbide particles have particle diameters of 0.25 μm, 0.5 μm and 0.8. mu.m, respectively.

In the present invention, in S4, the sintering temperature is 500-800 ℃, and the sintering atmosphere is a mixed atmosphere of nitrogen and hydrogen.

In the invention, the adhesive is selected from one or more of polyvinyl alcohol, polyvinyl acetate, dextrin and paraffin, and is preferably polyvinyl alcohol.

The invention also comprises a preparation method of the high-strength silicon aluminum carbide composite material, which is characterized by comprising the following steps:

s5.1, selecting the silicon aluminum carbide particles prepared by the method for preparing the high-strength silicon carbide particle reinforced aluminum matrix composite, and selecting the silicon aluminum carbide particles with the particle sizes of 8-12 microns, 20-40 microns and 50-80 microns respectively;

s5.2, uniformly mixing silicon aluminum carbide particles with the particle sizes of 8-12 microns, 20-40 microns and 50-80 microns according to a certain mass ratio, then adding 0.5-3% of adhesive, 0.5-2% of emulsion wax and 0.5-5% of pore-forming agent by mass ratio, uniformly stirring and sieving for later use;

s5.3, putting the material prepared in the previous step into a die to prepare a pre-sintered body;

s5.4, sintering the pre-sintered body in a vacuum weak reducing atmosphere sintering furnace to obtain a silicon-aluminum carbide prefabricated model;

s5.5, placing the silicon aluminum carbide prefabricated model into a mold in a vacuum differential pressure casting furnace, and injecting an aluminum alloy metal liquid into pores of the silicon aluminum carbide prefabricated model by a vacuum differential pressure casting method to prepare a composite material;

and S5.6, after cooling, putting the composite material into a heat treatment furnace for annealing treatment, thus obtaining the high-strength aluminum-based silicon carbide composite material.

Further, the mass ratio of the silicon aluminum carbide particles with the particle diameters of 8-12 μm, 20-40 μm and 50-80 μm is 10-20: 20-40: 30-70.

preferably, silicon aluminum carbide particles with the particle diameters of 10 μm, 30 μm and 60 μm are mixed according to the mass ratio of 10-20: 20-40: 30-70, then adding adhesive, emulsion wax and pore-forming agent.

In the invention, the adhesive is selected from one or more of polyvinyl alcohol, polyvinyl acetate, dextrin and paraffin, and is preferably polyvinyl alcohol; the pore-forming agent is selected from one or more of starch, carbon powder and ammonium oxalate, and is preferably starch.

The invention also comprises a high-strength silicon aluminum carbide composite material, which is characterized in that the high-strength silicon aluminum carbide composite materialThe high-strength silicon aluminum carbide composite material is prepared by the preparation method of the high-strength silicon aluminum carbide composite material according to any one of claims 5 to 9, the bending strength of the high-strength silicon aluminum carbide composite material is not lower than 600MPa, and the air tightness of the high-strength silicon aluminum carbide composite material is less than 10^－10Pa·m³/s。

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. according to the method for preparing the high-strength silicon carbide particle reinforced aluminum-based composite material and the composite material thereof, provided by the invention, small-particle-size silicon carbide particles are modified, then a silicon-aluminum carbide prefabricated model is obtained, and finally aluminum liquid is infiltrated by differential pressure to obtain the high-strength silicon-aluminum carbide composite material, so that the defects of easy agglomeration and difficult infiltration of submicron or nanoscale silicon carbide (the particle size is less than 1 mu m) are overcome, the problems of small-particle-size silicon carbide surface wettability and difficulty in pore reservation are solved, a new thought is provided for the preparation of the high-strength silicon-aluminum carbide composite material, and the defects of the existing pressure casting and stirring casting are overcome;

2. the preparation method can prepare the silicon aluminum carbide composite material with 50-70% volume fraction according to the proportion, and the silicon aluminum carbide composite material has excellent mechanical property, bending strength of more than 600MPa, good compactness and airtightness of less than 10^－10Pa·m³And/s, meets the requirements of military industry, has low roughness after processing, and is beneficial to carrying out later surface treatment and related electroplating and chemical plating work.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.