Plastic deformation characteristics of an Mg–3Al–1Zn alloy at low temperatures

Abstract

Low temperature tension behavior of an Mg–3Al–1Zn alloy is evaluated at the strain rates of 10−2/s, 10−3/s and 10−4/s, respectively. Within a test temperature range from 300K to 77K, the work hardening behavior and strain rate sensitivity of the examined alloy are characterized to reveal the plastic deformation mechanism varying with temperature from the point view of dislocation motion. With the observation of high initial work-hardening rate, high strain rate sensitivity and low activation volume at cryogenic temperatures, the dominated mechanism of dislocation motion is regarded as varying from dislocation interacting with forest dislocation above 173K, into overcoming lattice fraction below 173K, especially when deformed at 77K.