Formation of Sub-grain Structure Induced by Composition Segregation and Stacking Faults in Laser-Deposited Premixed Near-αTitanium Alloy and Ti_(2)AlNb Alloy Powders  

激光沉积预混合的近α钛合金和Ti_(2)AlNb合金粉末中成分偏析与层错诱导亚晶结构形成

作　　者：Liu Na Zhao Zhanglong Liu Yuli Feng Kaikai Zha Xiaohui Li Pu Xu Wenxin Yang Haiou Lai Yunjin 刘娜;赵张龙;刘郁丽;冯凯凯;查小晖;李璞;徐文馨;杨海鸥;赖运金(西北工业大学材料学院,陕西西安710072;西北工业大学凝固技术国家重点实验室,陕西西安710072;中国航发湖南动力机械研究所发动机研发部,湖南株洲412002;西安欧中材料科技有限公司,陕西西安710018)

机构地区：[1]School of Materials Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China [2]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China [3]Engine Development Department,AECC Hunan Aviation Powerplant Research Institute,Zhuzhou 412002,China [4]Xi’an Sino-Euro Materials Technologies Co.,Ltd,Xi’an 710018,China

出　　处：《稀有金属材料与工程》2024年第12期3281-3290,共10页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51974259);Xi'an Municipal Bureau of Science and Technology(21ZCZZHXJS-QCY6-0008);Industry-Academic Cooperation Project of Aero Engine Corporation of China(HFZL2020CXY021)。

摘　　要：Near-αtitanium alloy and Ti_(2)AlNb alloy powders premixed with different proportions were prepared on the near-αtitanium alloy substrate by laser deposition technique,and the microstructure characteristics were analyzed and discussed.Results show that numerous river-like sub-grain structures are formed inside the equiaxed B2 grains of the laser-deposited premixed titanium alloy powders with the proportion of Ti_(2)AlNb above 40wt%,whereas the needle-like structure within coarse columnarβgrains exist with the proportion of Ti_(2)AlNb below 40wt%.It is noteworthy that the decrease in laser power and scanning speed can accelerate the formation of sub-grain structures.Based on the analysis of experimental results,it can be inferred that the formation of sub-grain structure not only is related to the precipitation of O phase due to composition micro-segregation at sub-grain boundaries,but also is inseparable from the stacking faults caused by the internal stress during the laser deposition.通过激光沉积在近α钛合金基板上制备了不同比例的预混合近α钛合金和Ti_(2)AlNb合金粉末,并对2种粉末的微观组织演变和结构特征进行了分析和讨论。结果表明,Ti_(2)AlNb含量在40%(质量分数,下同)以上的激光沉积预混合钛合金粉末的等轴B2晶粒内形成了许多河流状亚晶粒结构,而Ti_(2)AlNb含量在40%以下的粗柱状β晶粒内则呈现针状结构。值得注意的是,降低激光功率和扫描速度可以促进亚晶粒结构的形成。基于实验结果的分析可以推断出,这种亚晶粒结构的形成不仅与亚晶界成分微偏析导致的O相析出有关,还与激光沉积过程中内应力诱导的堆垛层错密不可分。

关 键 词：laser deposition premixed titanium alloy powders sub-grain structure composition segregation stacking faults 

分 类 号：TG665[金属学及工艺—金属切削加工及机床] TG146.23[一般工业技术—材料科学与工程]