热挤压对粉末冶金6061铝合金显微组织和抗拉强度的影响

摘要

In order to improve the density and mechanical property of 6061 aluminum alloy prepared by powder metallurgy,hot extrusion process was applied to the 6061 alloy in sintered state.The effect of hot extrusion on microstructure and tensile strength of 6061 aluminum alloy was researched.The results show that the microstructure of the aluminum alloy in sintered state was equiaxed grain distributed uniformly.After hot extrusion, the grains were distributed like bandings and grain size decreased.The relative density of the aluminum alloy in sintered state was 96.67％ and relative density of the aluminum alloy after hot extrusion increased to 98.14％.The tensile strength increased from 112 MPa to 248 MPa after hot extrusion.The fracture type of the aluminum alloy in sintered state was ductile fracture and fracture type of the aluminum alloy in hot-extruded state was mixed mode of ductile fracture and intergranular fracture.%为提高粉末冶金制备6061铝合金的致密性和力学性能,对粉末冶金烧结态的6061铝合金进行了热挤压处理,研究了热挤压对6061铝合金显微组织和抗拉强度的影响.结果表明:烧结态铝合金组织为均匀分布的等轴晶,热挤态铝合金的晶粒呈带状分布,晶粒尺寸变小;烧结态铝合金的相对密度为96.67％,经热挤压后铝合金的相对密度提高到了98.14％;铝合金经过热挤压后,抗拉强度由112MPa提高到了248MPa;烧结态铝合金的断裂形式为韧性断裂,热挤压后铝合金的断裂形式为韧性断裂和沿晶断裂的混合型断裂.