Study On The Distribution Of SiC Particles And The Properties Of SiCp/Al Composites Fabricated By High Pressure Torsion

SiCp/Al matrix composites reinforced with light weight, high strength, high modulus, good dimensional stability, excellent thermal conductivity, abrasion resistance and corrosion resistance, etc., which in the top field of aerospace, special equipment, electronic packaging, and new energy vehicle technology has been widely applied, for the rapid development of materials science and technology nowadays. Currently, the traditional methods for preparing the material, even if combined with subsequent improvement processes (such as rolling, forging and reciprocating extrusion, etc.), have poor effect in improving the particle distribution, reducing harmful interface reaction and enhancing the interfacial bonding capacity. In this paper, study is based on SiCp/Al matrix composites, and high pressure torsion process with large plastic deformation is used to successfully prepare homogeneous, high-performance composite material. Metallographic observation, testing of relative density, microhardness and tensile, fracture scanning electron microscope (SEM) and interface energy dispersive spectroscopy (EDS) are used to deeply analyse the influences of different process parameters (temperature, pressure, reverse turns, SiC particle content and SiC particle size) on the distribution of reinforcements and properties of SiCp/Al matrix composites. The results show that:With increasing shear deformation suffered by the sample volume (ie the increasing of radius and number of turns), distribution of SiC gradually is improved, besides microstructure uniformity, relative density, hardness, tensile strength, elongation and the thickness of interfacial diffusion layer of composite material are increased. However, the SiC particle breakage leads by excessive shear deformation is serious, so that inhibit the improvement of all aspects of the material. Increased the amount of shear deformation at the same time improving the experimental temperature make density, hardness, structure uniformity and interfacial diffusion layer of the composite material improved. But if the temperature is too high, the deformation coordination liquidity between particles will be deteriorated, which hinder the improvement of mechanical properties of composites. Increasing the pressure can improve the hardness, density and microstructure uniformity of the material. However, excessive pressure could cause particles of SiC particles appear "second reunion" to increase the porosity and reduce the relative performance of the composites. Increasing the content of SiC particles can increase the hardness of the material, but reduce the uniformity and relative density, meanwhile tensile strength of the material increased first and then decreased and the elongation decreased gradually. With the increasing of SiC particle size, microstructure uniformity, hardness, relative density, tensile strength and elongation of the material are increased first and then decreased. SEM morphology analysis of fracture show that, the increasing of number of turns could increase toughness fracture trend of composites. With SiC particle content increasing, the composite material emerges brittle transition. When SiC particle size is increased, the composite material exhibits mixed fracture mode with toughness fracture and brittle fracture.