电子束成形TC18钛合金晶体取向规律研究  

Crystal Orientation Distribution of TC18 Titanium Fabricated by Electron Beam Wire Deposition

作　　者：董伟[1] 黄志涛[1] 刘红梅[2] 杨光[1] 杨洋[1] 杨帆[1] DONG Wei HUANG Zhitao LIU Hongmei YANG Guang YANG Yang YANG Fan(BeijingAeronatical Manufacturing Technology Research Institute, Science and Technology on Power Beam Processes Laboratory, Beijing 100024, China School of Materials Science andEngineering, University of Science and Technology Beijing, Beijing 100038, China)

机构地区：[1]北京航空制造工程研究所高能束流加工技术重点实验室,北京100024 [2]北京科技大学材料科学与工程学院,北京100083

出　　处：《材料研究学报》2017年第3期203-210,共8页Chinese Journal of Materials Research

基　　金：国家自然科学基金(51205178);甘肃省自然科学基金(1208RJZA189)~~

摘　　要：采用电子束熔丝成形工艺制备TC18钛合金试件,研究了其柱状晶组织的生长和晶体取向的分布规律。结果表明,用电子束熔丝成形工艺制备的TC18钛合金,其宏观金相组织为沿竖直方向生长的粗大柱状晶,以外延生长的方式从熔池底部长大。受成形过程中特殊传热条件的影响,电子束熔丝成形钛合金组织中的TC18钛合金晶体形成特定方向的择优取向,α、β两相晶体取向分布都有明显的规律。在成形组织外延生长的情况下,β相向α相晶体结构的转变具有继承性。其中大多数β晶粒有<001>方向的强丝织构,柱状晶间β相的宏观取向也有明显的特征,分布方向集中为TD、LD及法面ND。β→α转变严格遵循Burgers取向关系,由同一个母相β晶粒内析出的片层α/α满足Burgers取向关系所要求的取向差分布,柱状晶内的α主要有6种取向,β→α转变过程有较强的变体选择。TC18 titanium was fabricated by Electron Beam Wire Deposition（EBWD）. The distribution of crystal orientation and columnar structure of the alloy was investigated. The results show that the macrostructure of TC18 titanium consisted of large columnar grains orientated perpendicular to the workbench plane. The forming of columnar structure is a process of directly epitaxial growth of the β grains on the melt-pool bottom. Crystal orientation distribution has clear regularities, β-α phase structure transition has inherited characteristics. Most of the β grain with 〈001〉 direction present a strong fiber texture with orientation difference less than 10°. There are obvious characteristics among different columnar crystals and distribution direction for TD, LD and normal surface ND. Burgers orientation relation was strictly followed in the process of β→α. The lamella α phase precipitates within the same β grain satisfy the Burgers orientation relationship. There are 6 kinds of orientation for α phase in a columnar grain and there exists strong variant choice of orientations for β→α transformation process.

关 键 词：金属材料 TC18钛合金 电子束熔丝成形 柱状晶 外延生长 织构 

分 类 号：TG146[一般工业技术—材料科学与工程]