Effect of ageing treatment process on the microstructure development and mechanical properties of 6082 Al alloy

Abstract

Different ageing treatment process was conducted to improve the mechanical properties of 6082 Al alloy. Tensile results show that as compared to the T6 sample, the ultimate tensile strength, yield strength and elongation of the T6I6 sample increase by 3.2 %, 3.5 %, and 47.3 %, respectively, the ultimate tensile strength, yield strength and elongation of the RD+T6I6 sample increase by 12.9 %, 11.8 % and 12.5 %, respectively. Microstructural results reveal that holding at 65 ºC for 336 h after pre-ageing promotes the formation of GP zones and stimulates the transformation of GP zones into β" precipitates during subsequent ageing at higher temperature. The introducing of the asymmetric rolling deformation after pre-ageing can reduce the average grain size, induce high-density dislocations and increase the average Taylor factor (M) due to the increasing of S and Brass texture. The dislocations have a good effect on the formation of fine β" precipitates during subsequent ageing. This microstructure is responsible for the improvement of the mechanical properties.