Study on the Dynamic Recrystallization Critical Stress of AZ91 Magnesium Alloy

Abstract

The true stress-strain curves of AZ91 magnesium alloy as-homogenized were studied with compression tests on Gleeble 3500 thermal simulated test machine at 200°C—400°C and strain rate range of 10-3S-1 — 5S-1. Critical recrystallization behavior of AZ91 magnesium alloy was investigated by using strain hardening rate. The relationship between critical stress of dynamic revrystallization and temperatures and strain rates is determined by the curves between strain hardening rate and flow stress. According to the irreversible principles of thermo dynamics, the critical stresses at different temperatures and strain rates are calculated by two derivative of θ—σ curves. The map of the critical stress-temperatures-strain rates is established.