Effects of Microstructures on the Tensile Properties and Corrosion Resistance of High-Purity Magnesium

Abstract

The microstructure, tensile properties at room temperature and corrosion rate in the 0.9% NaCl solution of the as-cast, as-extruded and as-drawn high-purity magnesium (99.99wt.% Mg) were experimentally investigated, respectively. Due to the coarse grains, both the tensile properties and corrosion resistance of the as-cast high-purity Mg were the lowest among the three states specimens, the yield strength (YS), ultimate tensile strength (UTS) and the elongation (EL) were 26.6MPa, 69.2MPa and 5.6%, respectively. The mass-loss rate of the as-cast high-purity Mg in the NaCl solution was 0.44g⋅m-2⋅h-1. For the as-extruded high-purity Mg, as the grains was remarkably refined, the YS, UTS and EL increased to be 108.3MPa, 152.7MPa and 27.0%, respectively, and the mass-loss rate become slower to be 0.25g⋅m-2⋅h-1. Attributed to the further refined grains, the YS, UTS and EL of the as-drawn high-purity Mg increased to 134.1MPa, 199.4MP and 15.3%, respectively, and the mass-loss rate reduced to be 0.12g⋅m-2⋅h-1. The experimental results in the present research indicated that the grain refinement can effectively improve both the mechanical properties and corrosion resistance of the high-purity Mg.