In this work, a thermodynamically consistent constitutive framework is introduced that is capable of reproducing the significant time-dependent behaviour of austenite-to-bainite phase transformations. In particular, the aim is to incorporate the effect of these diffusion-controlled processes by plasticity-like evolution equations instead of incorporating related global diffusion equations. To this end, a variational principle for inelastic solids is adopted and enhanced by an additional term. This term essentially contributes to the evolution equations for the phase volume fractions of several crystallography-based bainite variants. Due to the specific modifications, special attention has to be paid with respect to the fulfilment of thermodynamical consistency, which can be shown to be unconditionally satisfied for the newly proposed modelling framework. The phase transformation model itself is based on the convexification of a multi-well energy density landscape in order to provide the effective material response for possible phase mixtures. Several material parameters are determined via parameter identification based on available experimental results for 51CrV4, which also allow the quantitative evaluation of the predicted results.

在这项工作中，引入了一种热力学一致的本构框架，该框架能够再现奥氏体到贝氏体相变的显着时间相关行为。特别是，其目的是通过类塑性演化方程来结合这些扩散控制过程的影响，而不是结合相关的全局扩散方程。为此，采用了非弹性固体的变分原理，并通过附加项加以增强。该术语主要有助于几种基于晶体学的贝氏体变体的相体积分数的演化方程。由于特定的修改，必须特别注意满足热力学一致性，可以证明对新提出的建模框架无条件满足。相变模型本身基于多孔能量密度景观的凸化，以便为可能的相混合物提供有效的材料响应。几个材料参数是通过基于 51CrV4 的可用实验结果的参数识别来确定的，这也允许对预测结果进行定量评估。