Effect of pressureless sintering temperature on microstructure and mechanical properties of 15%SiC/2009Al composite

Abstract

In view of the problems of high preparation cost and low preparation efficiency of traditional powder metallurgy process, 15%(volume fraction, the same below)SiC/2009Al composite was prepared by cold isostatic pressing combined with pressureless sintering and hot extrusion process. The effect of different sintering temperatures (600, 620, 640 ℃) on microstructure and mechanical properties of 15%SiC/2009Al composite was studied. The results show that sintering at 600 ℃, the bonding between SiC and the matrix is poor, more large-size pores can be observed under the microscopic level, the density of the material is low, and the mechanical properties are poor. Sintering at a high temperature of 640 ℃, the billet produces a large amount of liquid phase, and overflows onto the surface of the billet, which causes the core alloying elements to decrease.In addition, sintering at 640 ℃ will trigger a strong interface reaction, generate more large-size brittle phase, become the source of cracks in the material fracture process, resulting in a decrease in material properties; 620 ℃ is the best sintering temperature, and more liquid phase can fill part of the pores in the billet, thereby improving the density and interfacial bonding strength of the material, and the strength and plasticity of the composite material have obtained the best values, the tensile strength and yield strength reach 505 MPa and 345 MPa, respectively, and the elongation reaches 7.2%.

Keywords

• sic particle
• aluminum matrix composites
• cold isostatic pressing
• sintering temperature
• mechanical property