Temperature Effects on the Microstructures of Mg–Gd–Y Alloy Processed by Multi-direction Impact Forging

Abstract

A high strain rate multi-directional impact forging (MDIF) was applied to a solutionized Mg-Gd-Y-Zr alloy in the temperature range of 350-500 °C. Results demonstrate that the dominant deformation mode is twinning at a temperature below 400 °C, whereas at a medium temperature of 450 °C considerable continuous dynamic recrystallization was promoted by {10-12} extension twins. At a higher temperature of 500 °C, twinning activation was suppressed. New DRX grains were observed but their sizes were much bigger than those resulting from the MDIFed 50 passes at 450 °C, which are ascribed to the larger grain boundary mobility and atomic diffusion at 500 °C. Moreover, a non-basal weak texture was gained afterward MDIF at each temperature, which is credited to the MDIF process and the minor strain applied in each pass.

Microstructure, Tensile Properties and Work Hardening Behavior of an Extruded Mg–Zn–Ca–Mn Magnesium Alloy

“…14e, f, the volume fraction of twins clearly decreased with increasing extrusion speed, while the fraction of dimples present increased. This can be attributed to the relatively fine DRXed grain size (~ 0.90 μm) and high V DRX (~ 66.9%) giving rise to a weaker texture, which promotes dislocation slip and so enhances plasticity [61,62]. For the ZXM-350/0.01 sample, it exhibits the largest recrystallized grain size (~ 1.24 μm) and low volume faction of DRXed grains (~ 53.4%, in Fig.…”