Research Toward Sintering Improvement During Press and Sinter Processing of Mg and Mg Alloy Powders

Consolidation of magnesium (Mg) alloy powders by near shape forming methods offers significant opportunity for structural material light weighting. Experimental results to date indicate that Mg/Mg alloy powders can be consolidated using press and sinter processing to some extent. Attaining full density of Mg/Mg alloy powders using solid and liquid phase sintering is difficult apparently due to the presence of surface oxide layers impeding interparticle sintering. In this work, thermodynamic modeling was applied to determine the equilibrium phases formed at varying oxygen (O₂) concentrations for pure Mg and several Mg powder alloys. Complimentary sintering experiments in relatively O₂ free inert atmospheres were subsequently performed to investigate densification and interparticle neck formation during sintering. Additionally, all sintered powder compacts were characterized for density, microstructure, phase development, and microstructure composition. Results of this work are intended to increase understanding of solid and liquid state sintering of Mg/Mg alloy powders.