Mg-12Gd-2Y-Sm-0.5Zr合金最大抗拉强度的反常行为

he mechanical properties of Mg-12Gd-2Y-Sm-0.5Zr alloy were investigated from ambient temperature to elevated temperature. It was found that an anomalous changes of tensile strength occurred from 20 ℃ to 300 ℃: the Ultimate tensile strength of alloy is increased with the increasing of temperature, with a small loss of yield strength and increased effect of work hardening. At the same time, the mechanism of crack propagation transformed from Griffith crack theory to Orowan crack theory with the increasing of temperature. All these make the plastic deformation energy and the sub-critical crack propagation stress increased significantly. The above reasons cause the anomalous changes of tensile strength.