Microstructural Evolution and Precipitation Mechanism of α-phase in Ti-55531 Alloy Aged at High Temperature

摘要：

　　After two-stage annealing heat treatment process,the near β-Titanium alloys reveal a mixed microstructure containing lath-like α phase and finer acicular α phase in β matrix,leading to the improvement of strength-ductility balance.In this paper,the microstructural evolution and the behaviour of α precipitate during high temperature ageing process were investigated by SEM in a near β-Titanium alloy called Ti-55531.The relationship between α precipitates and the β grain orientation in high temperature was investigated by EBSD.The results show that the α-phase precipitated only at some places of the β grain boundaries at higher ageing temperature (~780 ℃); the amount of grain boundary α increased with the decreased of the ageing temperature; after ageing at 720 ℃ for 45 min,we found that the α-phase precipitated not only at grain boundaries but also within the grains.It seems that the precipitation of grain boundary α is strongly influenced by β grain boundary energy which means that grain boundary α tends to form preferentially at high energy grain boundaries (high-angle grain boundaries); The α-phase precipitates more easily at the grain boundaries where the 110 plane of adjacent β grains have the same orientation.

关键词： Ti-55531 alloy High temperature ageing α-phase precipitate EBSD

作者: Xue Zhang Yi Chen Fengshou Zhang Junting Yang Yunjin Lai Hongchao Kou Jinshan Li Lian Zhou

作者单位: State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian 7100 Western Superconducting Technologies Co., Ltd, Xian 710016, China State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian 7100

会议类型: 国际会议

会议名称: the Chinese Materials Congress 2012(2012年中国材料大会(CMC2012))

会议地点: 太原

会议语种:英文

页码: 912-918

在线出版日期: 2012-07-13（万方平台首次上网日期，不代表论文的发表时间）