Spark plasma sintering and age hardening of an Al-Zn-Mg alloy powder blend

During sintering of blended powders by spark plasma sintering (SPS), short sintering times are opposed by the requirement of sufficient diffusion times to obtain chemical homogenization. In this study, commercially blended Al-alloy powder Alumix 431D was sintered by SPS at 425 °C for various sintering times. Microstructure analysis and mechanical properties of the consolidated components in the T1 and T6 states were evaluated. Densities between 97.5 and 99.7%TD were obtained across all hold times. After sintering for 60 min, microhardnesses of 91±8 and 143±6 HV were attained in the T1 and T6 conditions, respectively. The T1 samples had a flexural strength of 659±37 MPa and a flexural strain of 5.7±0.3%, compared to 552±43 MPa and 3.8±0.2% in the T6 temper. The mechanical properties of the T6 components were lower than those found in the literature. Extensive solution heat treatments of 2 and 4 h were performed prior to aging.