A new rhombohedral phase and its 48 variants inβtitanium alloy  

β钛合金中一种新的菱面体相及其48种变体

作　　者：Xin-nan WANG Ming HAN Fu-rong ZHANG Guang-ming ZHAO Zhi-shou ZHU 王新南;韩明;张福荣;赵光明;朱知寿(中国航发北京航空材料研究院先进钛合金重点实验室,北京100095;华东交通大学材料科学与工程学院,南昌330013)

机构地区：[1]Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China [2]School of Materials Science and Engineering,East China Jiaotong University,Nanchang 330013,China

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第9期2849-2863,共15页中国有色金属学报（英文版）

基　　金：financial supports from the National Natural Science Foundation of China(No.51071125);the Major Project of Department of Education of Jiangxi Province,China(No.GJJ210605)。

摘　　要：A new rhombohedral phase(termed R′)in a solution-aging-treated titanium alloy(Ti-4.5Al-6.5Mo-2Cr-2Nb-1V-1Sn-1Zr,wt.%)was identified.Its accurate Bravais lattice parameters were determined by a novel unit cell reconstruction method based on conventional selected-area electron diffraction(SAED)technique.The orientation relationship between R'phase and BCC phase was revealed.The results show that the R′phase is found to have 48crystallographically equivalent variants,resulting in rather complicated SAED patterns with high-order reflections.A series of in-situ SAED patterns were taken along both low-and high-index zone axes,and all weak and strong reflections arising from the 48 variants were properly explained and directly assigned with self-consistent Miller indices,confirming the presence of the rhombohedral phase.Additionally,some criteria were also proposed for evaluating the indexed results,which together with the Bravais lattice reconstruction method shed light on the microstructure characterization of even unknown phases in other alloys.在经固溶时效处理的钛合金(Ti-4.5Al-6.5Mo-2Cr-2Nb-1V-1Sn-1Zr,质量分数,%)中发现了一种新的菱形相(R′)。采用基于传统选区电子衍射(SAED)技术的新型单胞重构方法确定了其精确的Bravais晶格参数。揭示了菱形相与BCC相之间的取向关系。结果表明,R′相有48个晶体学等效变体,导致具有高阶反射、复杂的SAED花样图。在低指数和高指数带轴上采集一系列原位SAED图,48种变体产生的所有弱反射和强反射都得到了合理的解释,并直接标定了对应的Miller指数,证实了菱形相的存在。此外,还提出了一些评价标定结果的标准,这些标准与Bravais晶格重构方法相结合能使合金中未知相的微观结构表征得更加清楚。

关 键 词：titanium alloy rhombohedral phase Bravais lattice reconstruction VARIANT orientation relationship 

分 类 号：TG146.23[一般工业技术—材料科学与工程]