TAHA processing of a 6201 aluminium alloy†

Abstract

In order to gain better understanding of the effect of pre-aging on the tensile properties of 6201 Al alloy, different TAHA processes have been performed in this study. A 6201 AI alloy was first solution treated, followed by pre-aging at 135°C for 30 minutes (some specimens were without pre-aging). The specimens were then cold rolled to 60, 70 or 80% reduction in thickness followed by final aging at 140, 150 or 160°C for 1 to 20 hours. For specimens of 60% cold reduction, the ultimate tensile strength (UTS) and yield strength (YS) were significantly improved by pre-aging. The improvement in strengths by pre-aging was most (least) significant if the final aging temperature was 140°C (160°C). For specimens of 70% reduction, the improvement in UTS and YS by pre-aging was not as significant. For specimens of 80% cold reduction, lower strengths were found for pre-aged specimens as compared to specimens without pre-aging. Scanning electron microscopy revealed that there was close relationship between the fracture morphology and the resulting tensile properties. Proper combination of pre-aging and cold work led to finer, denser and more uniform distribution of precipitates which resulted in better tensile properties

Notes

†Paper presented at the 9th International Conference of Production Research, held in Cincinnati, USA, 17-20 August 1987