激光沉积预混合的近α钛合金和Ti2AlNb合金粉末中成分偏析与层错诱导亚晶结构形成
Formation of Sub-grain Structure Induced by Composition Segregation and Stacking Faults in Laser-Deposited Premixed Near-α Titanium Alloy and Ti2AlNb Alloy Powders
刘娜 1赵张龙 2刘郁丽 1冯凯凯 3查小晖 3李璞 3徐文馨 2杨海鸥 1赖运金4
作者信息
- 1. 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
- 2. 西北工业大学材料学院,陕西西安 710072
- 3. 中国航发湖南动力机械研究所发动机研发部,湖南株洲 412002
- 4. 西安欧中材料科技有限公司,陕西西安 710018
- 折叠
摘要
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a钛合金和Ti2AlNb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,Ti2AlNb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Ti2AlNb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.
Abstract
Near-α titanium alloy and Ti2AlNb alloy powders premixed with different proportions were prepared on the near-α titanium 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 Ti2AlNb above 40wt％,whereas the needle-like structure within coarse columnar β grains exist with the proportion of Ti2AlNb 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.
关键词
激光沉积/预混合钛合金粉末/亚晶结构/成分偏析/堆垛层错Key words
laser deposition/premixed titanium alloy powders/sub-grain structure/composition segregation/stacking faults引用本文复制引用
出版年
2024
NETL
NSTL
万方数据