Tailoring the microstructural characteristic and improving the corrosion rate of Mg-Gd-Ni alloy by heat treatment with different volume fraction of LPSO phase

Abstract

The microstructure and corrosion behaviors of Mg-Gd–Ni alloys with various long period stacking ordered (LPSO) phase volume fraction and heat treatments were investigated. Compared with as-cast alloys, the corrosion rates increased significantly after heat treatment, and increased with increasing volume fraction of LPSO phase, which may be due to the transformation of continuous bulk reticular LPSO phase to discontinuous rod-like and the precipitation of the lamellar 14 H LPSO phase, changing the corrosion propagation paths and providing more galvanic corrosion points for alloy with high LPSO phase volume fraction, resulting in corrosion rate of MgGd3Ni3 alloy increased significantly by 58.1%.