Influence of Hot Extrusion on Microstructure and Hardness of SiC Particle Reinforced Al-Zn-Mg-Cu Alloy Matrix Composite

In this paper, the microstructure and mechanical property of the Al-Zn-Mg-Cu aluminum matrix composite reinforced by SiC particles with the contents of 2.5, 4.5, and 6.5wt% through vacuum casting are studied. The homogenization treatment was conducted at 465°C heat insulation for 24h. The purpose of this study is to analyze hot extrusion influence on the microstructure and hardness of the Al-Zn-Mg-Cu aluminum matrix composite. SiCp under pre-processing possesses good wetability with the analysis of Laser Particle Sizer and XRD. Metallurgical microscope, XRD, SEM and EDS is applied to analyze the microstructure of the Al-Zn-Mg-Cu aluminum matrix composite. It has proved that the hot extrusion can effectively improve the homogenization of SiCp and dissolve the second rough phases to reinforce the dispersal of CuAl₂ and MgZn₂ phase. The hardness of Al/SiCp composite rises as the increase of the SiCp content. It is shown that when the SiCp content is above 5%, its hardness obviously reinforced as well as that of the Al/SiCp composite.