|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||Influences of Pre-existing Defects on the Morphology and Variant Selection of Precipitates in Alpha/Beta Ti-alloys
||Di Qiu, Rongpei Shi, Pengyang Zhao, Weijie Lyu, Yunzhi Wang
|On-Site Speaker (Planned)
Pre-existing crystalline defects, such as dislocations, grain boundaries (GBs) and existing precipitates, have been found to have significant influences on the subsequent development of precipitate microstructures during solid state phase transformations. Through phase field simulations incorporating stress fields of various defects as inputs, we show that 1) for 1-dimensional (1-D) single dislocations, edge dislocations interact with alpha nuclei with larger interaction energy than screw dislocations, leading to a greater degree of variant selection (VS); 2) for 2-D low angle GBs modeled by dislocation networks, alpha allotriomorphs and GB side-plates compete with each other during precipitation and the final morphology exhibits a strong correlation with the GB structures and 3) for existing (primary) alpha precipitates, they may induce the nucleation of certain variants of secondary alpha. The simulation results are analyzed in details from the views of energy and crystallography, and compared with experimental observations.
||Planned: Supplemental Proceedings volume