关于相变本构关系的一个一维模型

AN ONE-DIMENSIONAL PHASE TRANSITION CONSTITUTIVE MODEL

以一含缺陷的一维杆模型模拟实际材料的相变得到了率相关相变本构关系。该本构预测的硫化镉(CdS)晶体的冲击相变波形,除了前驱波后的松弛沟外,在主要特征方面能很好地描述实验波形。预测的波形在形态上与Fe和锑化铟(InSb)的相变波形比较接近。

Defects are always existing in real materials,which cause stress concentration.When phase transition takes place,new phase nuclei form first at the positions of defects and then grow via phase boundary propagation.There is a certain relationship between the propagation velocity of phase boundary and the driving force,i.e. the Gibbs free energy difference between two phases.From this point,we have studied the phase transition process of real material with a model of rod containing defects,and have derive a rate dependent phase transition constitutive relation which in form is similar to generalized Maxwell model.Based on this model,stress profiles of CdS transformation under shock loading were calculated.Results show that our constitutive model can describe the main characteristics of the experimental phenomenon,except the large stress relaxation after the precusor.The calculated wave profiles are quite close to those of Fe and InSb,which suggests this model can be applicable to materials other than CdS.