报告题目 (Title)：Phase-field modeling of α precipitation in the presence of crystalline defects in α/β Titanium alloys（α/β钛合金晶体缺陷附近α相析出机制的相场法研究）
报告人 (Speaker)：邱嫡 讲师（上海大学材料基因组工程研究院）
报告时间 (Time)：2021年12月1日(周三) 15:00
报告地点 (Place)：宝山校区西区E楼106
邀请人(Inviter)：李永乐 副教授
主办部门：理学院物理系
摘要：
Crystalline defects introduced during thermo-mechanical processing will influence the spatial orientation, distribution and morphology of α phase, leading to drastically different microstructures and, consequently, considerable variations in mechanical properties. Such influences could be quite complex as the orientation variants of α precipitates within every single β grain are up to 12 types, among which only a subset would be preferred by crystalline defects. So far, extensive experimental characterizations have provided certain correlation between processing and microstructure. Nevertheless, a direct dynamic relationship between fundamental crystalline defects and α precipitation is still beyond the capacity of current experimental techniques. To this end, we developed a three-dimensional (3-D) phase field simulation, together with dislocation theory and anisotropic elasticity, to systematically investigate the effects of crystalline defects with different dimensions, i.e., dislocations (1-D), grain boundaries (2-D) and pre-existing α lath (3-D) on the dynamic precipitation behavior of α phase and microstructure development during diffusional β→α transformation. The precipitation behavior of α phase is found to alter with the types of defects. This work provides theoretic evidence and prediction for the formation of typical microstructure in Ti-6Al-4V alloys, and proposes a useful framework and new thoughts for the study of relevant issues within other alloy systems.
