Microstructure, texture and mechanical properties of coarse-grained Mg-Gd-Y-Nd-Zr alloy processed by multidirectional forging

Multidirectional forging (MDF) was applied to severely deform the homogenized coarse-grained Mg-Gd-Y-Nd-Zr alloy under decreasing temperature condition, and the microstructure, texture and tensile properties of the MDFed alloy were investigated in the current study. With the increase of MDF passes, the volume fraction of the fine recrystallized grains was remarkably increased, and the average grain size decreased from 200 μm to 5.4 μm after three MDF passes, but after that, the average grain size was almost unchanged, ultrafine grains (UFGs) with an average grain size of 5.1 μm were uniformly evolved after six MDF passes. The basal texture was gradually weakened with increasing the MDF passes, which resulted from cooperative effect of dynamic recrystallization, dynamic precipitation and the change direction of the MDF force. The yield strength, ultimate tensile strength and elongation to failure were enhanced with increasing the MDF passes.