Improvement of ultimate tensile strength by artificial ageing and retrogression treatment of aluminium alloy 6061

In the present work, the relation between ageing and retrogression temperatures on Al 6061 alloy hardness and ultimate tensile strength (UTS) was studied. It was found that higher UTS and hardness were obtained at higher ageing, retrogression temperatures, and lowest retrogression time. Controlling these parameters, alloy UTS has been improved 12% over T6 temper, showing a 40% reduction in time consumption during the thermal treatment. By means of a multiple linear regression method, a correlation has been established between UTS, hardness, and time/temperature for ageing and retrogression regimes, This correlation can be used to select adequate ageing temperature and retrogression time-temperature in order to obtain both specific UTS and hardness on aluminium 6061 alloy.