Dependence of thermomechanical response on Cu content in a hardenable Al-Si-Mg alloy

Abstract

In this study, we investigated the effect of Cu content on the thermomechanical response of a precipitation-hardenable Al-Si-Mg alloy produced by the casting and rolling processes. The Cu content ranged from 0.35 to 0.95 wt.%, while the alloy maintained fixed amounts of Si and Mg. The thermomechanical process included pre-aging (PA), stretching by 4% (S), and post-aging (T6). The results were based on the yield strength (YS) and the thermomechanical response was defined as YS_PAST6 – YS_T6. The findings indicated that at low and medium levels of Cu, the YS of the samples in PA and PAS conditions remained mostly constant at 206 and 281 MPa, respectively. However, it increased from 334 (low Cu) to 351 MPa (medium Cu) when the PAST6 process was completed. At a high level of Cu content, the YS_PA and YS_PAS enhanced to 221 and 298 MPa, respectively. Nevertheless, the YS after complete PAST6 was 349 MPa, slightly lower than that of the alloy containing medium Cu level. It was observed that the thermomechanical response of the alloy is at its maximum (50 MPa) when the amount of Cu is around the middle of the defined range.