Effect of heat treatment on strength and ductility of 6061Al alloys by hot extrusion of powder

The effect of solid solution and peak aging on the microstructures and mechanical properties of the hot extruded 6061 Al alloys made by powder was studied. The microstructures of as-extruded,solid solution and ageing treatments were investigated and the tensile properties were tested. The results showed that the fine and homogeneous grain structure was obtained in as-extruded Al alloys,and there were lots of precipitated phase particles( Mg2Si) in the matrix. After solution and ageing treatment( 530 ℃ × 1 h + 170 ℃ × 6 h),the constituents of matrix were composed of α-Al,strengthing phases β″-Mg5Si6 and little amount of β'-Mg2 Si,tensile strength and elongation were 311 MPa and 10%,respectively. In contrast with as-extruded materials,the tensile strength of the heat treated 6061 alloys increased nearly by 160%.