Deformation mechanism of fine grained Mg–7Gd–5Y–1.2Nd–0.5Zr alloy under high temperature and high strain rates
Wanru Tang, Zheng Liu, Shimeng Liu, Le Zhou, Pingli Mao, Hui Guo, Xiaofang Sheng
Abstract
Fine grained Mg–7Gd–5Y–1.2Nd–0.5Zr alloy was investigated by dynamic compression tests using a Split Hopkinson Pressure Bar under the strain rates in the range 1000–2000 s − 1 and the temperature range 293–573 K along the normal direction. The microstructure was measured by optical microscopy, electron back-scattering diffraction, transmission electron microscopy and X-ray diffractometry. The results showed that Mg–7Gd–5Y–1.2Nd–0.5Zr alloy had the positive strain rate strengthening effect and thermal softening effect at high temperature. The solid solution of Gd and Y atoms in Mg–7Gd–5Y–1.2Nd–0.5Zr alloy reduced the asymmetry of α-Mg crystals and changed the critical shear stress of various deformation mechanisms. The main deformation mechanisms were prismatic slip and pyramidal 〈a〉 slip, {102} tension twinning, and dynamic recrystallization caused by local deformation such as particle-stimulated nucleation.