多次相变中固-固相变形核的相场法模拟

Phase field simulation of nucleation of solid-solid phase transformation in multiple phase transition

综合考虑晶界缺陷与溶质在晶界处富集对区域自由能的影响,建立多次相变中固-固相变的形核模型,采用该模型对Fe-C二元合金多次相变中固-固相变的形核过程进行模拟研究.结果表明:材料多次相变微观组织演化是一个连续的过程,后次相变受前次相变结果的影响;受到形核功和自由能的影响,铁素体晶粒优先在奥氏体的晶界处形核;不同形核位置的铁素体有不同的形态;新模型可以用于相场法研究材料多次相变中微观组织连续演化,能真实地再现多次相变中固-固相变的形核过程.

Considering comprehensively the influence of grain boundary defects and solute concentration on regional free energy,the nucleation model of solid-solid phase transformation in multiple phase transition is established and the nucleation process of solid-solid phase transformation of Fe-C binary alloy during multiple phase transition is investigated simulatively by using this model.The result shows that the microstructure evolution of the multiple phase transition of material will be a continuous process,so that the latter phase transformation will be affected by the former one plus the nucleation energy and free energy.The ferrite grains will preferentially nucleate at the grain boundaries of the austenite grains with different morphology at different nucleation center.New model can be used to study the continuous evolution of the microstructure with phase-field method during the multiple phase transition of the material and reproduces the nucleation process of the solid-solid phase transformation in multiple phase transitions.