Effects Of Microstructure And Properties On SiC_p/7055 Aluminum Matrix Composites By Extrusion Deformation

At present,in this research boom of material development and application,aluminum-based composite materials have always been in a crucial position.Because of its high strength,high modulus,excellent abrasion resistance and low thermal expansion coefficient,aluminum metal matrix composite materials have attracted many researchers' study and attention.Because extrusion has always been one of the important methods for forming and processing high-performance aluminum composites.The influence of extrusion parameters on its structure and properties is closely related.Therefore,it is particularly important to study the impact of different extrusion processes on its microstructure evolution and properties.To this end,this paper takes the 17% SiC_p/7055 aluminum-based composite material prepared by spray deposition as the research object,and uses X-ray diffraction and EBSD texture analysis methods to study the structural evolution and performance changes of the composite material during extrusion deformation In-depth research and analysis.Prior to the study of its extrusion deformation,the heat treatment and high temperature deformation of the composite were studied.The above research results show that:?1?The best solid solution process for 17% SiCp/7055 aluminum-based composites is:at 450 °C keep 1 hour.The solution treatment increased the yield strength of the composite from 171 MPa to 276 MPa and the tensile strength from 329 MPa to 435 MPa.The elongation of the composites was increased from 5.8 to 10.2.After aging at 140 °C for 24 hours,the composite has excellent microstructure and microhardness of 198 HV.?2?When the tensile deformation at high temperature is 300 °C and the strain rate is 0.01s^-1,the plastic deformation capacity of the as-stretched sample is greater than that of the DP.A large number of coarse second-phase particles were precipitated in the DP,which reduced the plasticity of the composite material and reduced its strain sensitivity index m from 0.18 to 0.02.?3?The composite material is extruded at 400 °C and an extrusion ratio of 20.The composite material has excellent mechanical properties,its tensile strength reaches 413 MPa,and its elongation reaches 9.5%,its comprehensive properties are excellent.During extrusion deformation,the?111? crystal plane texture of the composite matrix changes significantly.Dynamic recrystallization that occurs during extrusion will weaken the texture and reduce the mechanical properties of the composite.