AZ31B镁合金和6065铝合金动态压缩行为数值模拟

Numerical simulation for dynamic compression behavior of AZ31B magnesium alloy and 6065 aluminum alloy

为了研究帽状试样AZ31B镁合金和6065铝合金在动态压缩变形过程中的温度、应力与应变演变规律,采用Johnson-Cook本构方程和累积塑性损伤方程进行了数值模拟,运用有限元软件ANSYS/LS-DYNA模拟了AZ31B镁合金和6065铝合金帽状试样的动态变形过程.结果表明,两种合金的裂纹萌生和扩展过程相似,局域化变形带内塑性应变由内向外对称分布.相比于AZ31B镁合金,6065铝合金的塑性应变影响区域更为狭小,其应变和应变率硬化效果更强.6065铝合金的变形温度能够达到其动态再结晶临界点,因而易于绝热剪切带的形成.

In order to study the evolution rule of temperature,stress and strain of AZ31 B magnesium alloy and 6065 aluminum alloy hat-shaped specimens in the dynamic compression deformation process,the numerical simulation was carried out with both Johnson-Cook constitutive equation and accumulative plastic damage equation. The dynamic deformation process of both AZ31 B magnesium alloy and 6065 aluminum alloy hat-shaped specimens was simulated with ANSYS/LS-DYNA finite element software. The results showthat the crack nucleation and propagation processes of two alloys are similar,and the plastic strain in the localized deformation band shows the symmetrical distribution from interior to exterior. Compared with AZ31 B magnesium alloy,the plastic strain affected zone in 6065 aluminum alloy is narrower,while the strain and strain rate hardening effect is stronger. The deformation temperature of 6065 aluminum alloy can exceed its critical dynamic recrystallization point,which is beneficial to the formation of adiabatic shear band.