Ductility enhancement of EW75 alloy by multi-directional forging

Abstract

In this study, the Mg–7Gd–5Y–1Nd–0.5Zr alloy can reach a high ductility by the process of multi-directional forging, and the evolution of the microstructure, texture and the mechanical properties were discussed systematically. The results show that after the solutionized sample was multi-forged at 500 °C, its grain size can be refined from 292 um to 58 um. As the forging temperature decreased, fine particles precipitated in the matrix. The volume fraction of the particles increased with the forging temperature decreasing, so the nucleation and growth of crystallization were strongly restricted. There was no recrystallization as the forging temperature fell to 410 °C, and the severe deformed grains distributed as streamlines perpendicular to the final compression axis. The texture intensity decreased with increasing forging passes. The sample with best ductility was obtained after compressed at 470 °C, with an elongation to failure of 21% at room temperature, which is increased by 200%, in comparison with that of the samples in solutionized condition. EBSD results revealed that the mean grain size was 15 um. Refined grains as well as the weakened texture were the key factors to its high ductility.

Keywords

• Mg alloys
• Ductility
• Multi-directional forging
• DRX
• Precipitates