Synergic effect of high temperature and high pressure on consolidation of Mg-4Y-3Nd powder by spark plasma sintering

Abstract Sintering of magnesium powder is often affected by the oxide layer, which is present on the powder already after gas-atomization. Its negative consequence demonstrates itself usually by limited diffusion between the individual powder particles and formation of compact 3D net-like structures, which promote crack propagation during mechanical loading. This work shows that magnesium-rare earth metals alloys, in this case Mg-4Y-3Nd, can benefit from the utilization of sufficiently high sintering temperature and pressure during the spark plasma sintering. A thorough analysis of the powder boundaries morphology and chemical composition revealed that application of temperature near the eutectic point of Mg-Y/Nd system together with high pressure results in severe diffusion of both Y and Nd into the powder boundaries. Consequently, local change in the chemical composition led to partial melting and the oxide shells became unstable and shattered. As a result, the interparticle diffusion was intensified and the powder consolidation became successful.