Improved ductility of Mg–3Gd–0.6Zr alloy by cuboid-shaped phase: experiments and first-principle calculations

Abstract

A casting Mg–3Gd–0.6Zr alloy was designed to evaluate the effect of cuboid-shaped phase on its mechanical properties. The morphology of cuboid-shaped phase was correlated with the directional covalent bonding between Gd atoms and H atoms along <100 > directions. The cuboid-shaped phase can be eliminated by a designed annealing treatment, without grain coarsening simultaneously. The ductility of as-cast alloy is about 20% higher than that of the annealed one. The improvement of ductility was caused by cuboid-shaped phase in three aspects: first-principle calculations, hydrogen embrittlement and crystal imperfections.