摘要
As-forged WSTi6421 titanium alloy billet afterβannealing was investigated.Abnormally coarse grains larger than adjacent grains could be observed in the microstructures,forming abnormal grain structures with uneven size distribution.Through electron backscattered diffraction(EBSD),the forged microstructure at various locations of as-forged WSTi6421 titanium alloy billet was analyzed,revealing that the strength of theβphase cubic texture generated by forging significantly influences the grain size afterβannealing.Heat treatment experiments were conducted within the temperature range from T_(β)−50°C to T_(β)+10°C to observe the macro-and micro-morphologies.Results show that the cubic texture ofβphase caused by forging impacts the texture of the secondaryαphase,which subsequently influences theβphase formed during the post-βannealing process.Moreover,the pinning effect of the residual primaryαphase plays a crucial role in the growth ofβgrains during theβannealing process.EBSD analysis results suggest that the strength ofβphase with cubic texture formed during forging process impacts the orientation distribution differences ofβgrains afterβannealing.Additionally,the development of grains with large orientations within the cubic texture shows a certain degree of selectivity duringβannealing,which is affected by various factors,including the pinning effect of the primaryαphase,the strength of the matrix cubic texture,and the orientation relationship betweenβgrain and matrix.Comprehensively,the stronger the texture in a certain region,the less likely the large misoriented grains suffering secondary growth,thereby aggregating the difference in microstructure and grain orientation distribution across different regions afterβannealing.
研究了β退火后的WSTi6421钛合金锻坯,其组织中出现尺寸大于周边晶粒的异常粗大晶粒,并形成了尺寸分布不均匀的异常晶粒组织。通过电子背散射衍射(EBSD)表征了WSTi6421钛合金锻坯上不同位置的锻态组织,发现锻造形成的β相立方织构的强度对β退火后的晶粒尺寸起着重要作用。在T_(β)−50℃~T_(β)+10℃温度区间内开展热处理实验并观察宏观及微观组织。结果表明,锻造产生的β相立方织构影响了次生α相的织构,在经β退火后进一步影响了退火过程中形成的β相,并且残余初生α相的钉扎效应对β退火过程中β晶粒的长大过程中起着重要作用。EBSD分析结果表明,锻造时形成的β相立方织构的强度影响了β退火后β晶粒取向分布的差异。同时,β退火过程中立方织构中大取向晶粒的演变表现出一定的选择性,受到初生α相的钉扎效应、基体立方织构强度和β晶粒与基体取向关系的多重影响。总体而言,区域内织构强度越强,大错位晶粒进行次生生长的可能性越小,进一步加剧了β退火后不同区域微观结构和晶粒取向分布的差异。
出处
《稀有金属材料与工程》
北大核心
2025年第2期354-362,共9页
Rare Metal Materials and Engineering
基金
Key Research and Development Plan of Shaanxi Province(2023-YBGY-493)。
