金属塑性变形的本构模型研究

根据位错动力学理论,忽略动态应变时效因素,将塑性变形的流变应力分解为非热应力、热激活应力和粘拽阻力3部分,建立了一个基于物理概念的本构模型。对HSLA-65结构钢的力学行为进行了研究,试验温度为77～700K,应变率为0.001～0.1s-1,真实塑性应变超过60%。结果表明,塑性流变应力随温度的降低、应变和应变率的增加而增大;在一定的温度和应变率范围发生动态应变时效现象,并且随应变率的提高,该现象将移向更高的温区。通过模型预测与试验结果的比较可知,所给本构关系能很好地描述较宽的温度与应变率范围内的塑性流变应力。

Constitutive Model of Plastic Deformation for Metal

Based on the theory of dislocation dynamics,a physically-based constitutive model is established in which the dynamic stain aging effects are excluded,the flow stress of plastic deformation is remlved into three parts:athenml component,thermally-activated stress,and viscous drag.The mechanical behaviors of the steels HSLA-65 are studied at temperature of 77～700K and stain rates of 0.001～0.1s~(-1),strains over 60%.The results show that plastic flow stresses increases with temperatures decreasing,strain and strain rate increasing.Dynamic stain aging occurrs in a certain temperature and strain rate region.The temperature region of the phenomenon will shift to higher as strain rate increasing.The plastic flow stresses can be deseribed well at a wide range of temperatures and strain rates by comparing the results predicted and measured.