Effect of preset twins on aging precipitates and mechanical properties of Mg-5Gd-3Y-0.5Zr alloy

Abstract

Preset twins in Mg-5Gd-3Y-0.5Zr (GW53K) alloy, the effects of preset twins on the aging precipitates and mechanical properties of GW53K alloy were thoroughly investigated. The results showed that the preset twin boundaries provided nucleation locations for the aging precipitates and promoted the aging precipitation behavior of GW53K alloy. High density of lath-like twins increased the strength of the alloy. Lattice distortions were generated around twin boundaries, which impeded dislocation slip and produced stress concentration, so that the solute atoms Gd and Y easily clustered there to form precipitates. Precipitates could form ''barriers'' with twin boundaries and increased the ability of twin boundaries to block dislocation slip and the movement of twins, which further improved the strength of the alloy. However, the presence of twins accelerated the fracture process of GW53K alloy and reduced plasticity.

Keywords

• Mg-Gd-Y-Zr
• Preset twins
• Precipitates
• Mechanical property