基于动态再结晶的铸态AZ31B镁合金本构方程

Constitutive Equation of As-cast AZ31B Magnesium Alloy Based on Dynamic Recrystallization

摘要:

通过GLEEBLE压缩实验获得铸态AZ31B镁合金真应力应变曲线,本文从真应力应变曲线出发,通过数值分析获得临界应力应变模型、饱和应力模型和稳态应力模型等多种应力模型。同时,结合位错理论和动态再结晶动力学,根据镁合金在变形过程中发生动态在结晶的临界点,将应力应变曲线分为两段,分别对以动态回复为主的曲线和以动态再结晶为主的曲线建立本构模型,分析并得出了动态再结晶百分数与基于动态再结晶下的流变应力之间变化规律。

Abstract:

The true stress-strain curves of as-cast AZ31B magnesium under different temperature and strain rate can be obtained from GLEEBLE compression experiment. Critical strain model, saturated stress model and static stress model can be received by analyzing true stress-strain curves. Based on the classical dislocation density theory and the dynamic recrystallization (DRX) kinetics models, a two-stage constitutive model considering the effect of work hardening-dynamic recovery and DRX is developed for the as-cast AZ31B magnesium alloy. And the relation between the percentage of DRX and flow stress is obtained.