微观结构
材料科学
烧结
合金
冶金
相(物质)
钛合金
钛
对偶(语法数字)
艺术
化学
文学类
有机化学
作者
Jue Cheng,Zhibin Zheng,Jingli Zhang,Mingyang Li,M. Zhang,Xinyu Mao,Yaonan Hou,Peng-Fei Zhang,Mingjia Li,Junjie Xu,Longlong Dong,Guozhe Sun
标识
DOI:10.1016/j.msea.2024.146294
摘要
The improvement of microstructure and mechanical properties of Ti alloys is of great significance for their industrial application. In this study, a developed multi-step hot deformation process was employed to regulate the grain boundaries (GBs), hetero-phase boundaries (PBs) and dislocation structure for dual-phase titanium alloy. The effects of accumulative thermal deformation ratios from 33% to 75% (2–8 cycles) on the microstructure and mechanical properties have been investigated. It is found that the sintered sample shows a typical Widmanstätten structure without obvious pores and micro-cracks. However, with the increase of the deformation ratio, for the hexagonal close packed (HCP) Ti, the crystal orientations of {011¯0} and {1¯21¯0} were gradually transformed into {0001}, with the change of high-angle grain boundaries (HAGBs) to low-angle grain boundaries (LAGBs). The density of stored geometrically necessary dislocations (GNDs) density raised dramatically from 1.95×1014 m−2 to 6.5×1014 m−2, and various types of dislocations have been characterized. For the β phase, in the thermal deformation process, high density α´-precipitates with an average thickness below 20 nm had formed with Burgers relationship of {110}BCC//{0001}HCP and < 1¯11 > BCC//< 21¯1¯0 > HCP. Finally, the yield strength of the dual-phase titanium alloy increased dramatically from 881 MPa to 1178 MPa, and the ductility can still maintain at above 8.5%. The enhanced strength was mainly contributed by the increase of geometrically necessary boundaries (GNBs) and nano-lamellae boundaries (NLBs). Therefore, this strategy of combining hetero-phase boundaries (PBs) and dislocation engineering could open up new avenues to designing strong and ductile titanium matrix materials.
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