Sintering behaviour and mechanical properties of PM Al-Zn-Mg-Cu alloy containing elemental Mg additions

Abstract

A commercially available PM Al-5.5Zn-2.5Mg-1.6Cu (wt-%) alloy has been used to study the effect of elemental Mg additions, ranging from 0 to 4.5 wt-%, on its sinterability and mechanical properties after sintering and heat treatment of the W and T6 type. DSC experiments were performed to study the chemical reactions occurring during sintering. Results obtained from dilatometry and DSC experiments were used to aid determination of the optimum sintering cycles under nitrogen. DSC experiments performed on as sintered samples were used for the determination of the solution treatment temperature. The microstructure obtained after sintering of the experimental Al alloys was characterised by SEM and XRD. The mechanical properties of the alloys, both, in the as sintered and heat treated states were obtained from tensile testing and hardness measurements. Additional theoretical calculations, using the THERMOCALC programme, along with the experimental observations, were carried out as an alloy design method to suggest an alternative chemical composition and alloying strategy aimed at upgrading the sintering behaviour and mechanical properties of the present alloy.