Effects of Mg content on aging behavior of Al4CuXMg PM alloy

Starting with elemental (pre-mixed) powders for producing shaped powder metallurgy alloys provides some advantages over a pre-alloyed system. The premixed powders are softer than prealloyed powders and therefore by using premixed powders it is possible to have higher compact densities and within a longer die life. In this research work, elemental aluminum powder was mixed with copper and magnesium in various ratios. They were compacted, sintered and heat treated in order to produce light but strong Al-based powder metallurgy alloys. The main focus of this paper is on the effects of micro to macro scale addition of magnesium on the aging response of Al4Cu alloys. Four per cent Cu gives Al powder metallurgy alloy a good control of sintering and a large space for solution treatment. Minor addition of Mg with little amount of Fe, comes from the based Al and Cu powders, enhances the hardness values of Al4Cu powder metallurgy alloys. Highest hardness value was 118 HB obtained from 24 h aged Al4Cu2Mg alloy.

► Pre-mixed elemental Al-based P/M alloys were compressed and sintered successfully.
► Optimum compression pressure for pre-mixed Al P/M alloys was found as 400 MPa.
► Effects of thermal treatment on microstructure of Al4CuXMg alloys were highlighted.
► Hardness of Al4Cu P/M alloys was trebled by microalloying and thermal treatment.
► Iron, comes as an impurity, forms insoluble Al7Cu2Fe phase during aging treatment.