Investigation of the Sintering Fundamentals of Magnesium Powders

Abstract

Magnesium and its alloys are attractive for use in automotive and aerospace applications because of their low density and good mechanical properties. However, difficulty in forming magnesium and the limited number of available commercial alloys limit their use. Powder metallurgy (P/M) can be used to alleviate the formability problem through near-net-shape processing. The surface layer on Mg powders acts as a barrier to diffusion and sintering is problematic. X-ray photoelectron spectroscopy (XPS) was used to identify the composition of the layer, as well as a focused ion beam (FIB) process for obtaining thin films was utilized to prepare samples for analysis with transmission electron microscopy (TEM). Sintering of pure magnesium compacts has been studied by differential scanning calorimetry (DSC), which identified several decomposition reactions during heating. It was also found that alloying additions of calcium and yttrium promote surface layer disruption during sintering by DSC measurements and testing indicates improved mechanical properties.