钛铝金属间化合物电子束修复层显微组织演变  

Microstructure Evolution of Ti-Al Intermetallic Compound Electron Beam Repair Layer

作　　者：洪敏 王善林[1] 孙文君 吴鸣 徐勇[1] 陈玉华[1] Hong Min;Wang Shanlin;Sun Wenjun;Wu Ming;Xu Yong;Chen Yuhua(Jiangxi Provincial Key Laboratory of Aviation Component Forming and Connection,Nanchang Hangkong University)

机构地区：[1]南昌航空大学航空构件成形与连接江西省重点实验室

出　　处：《特种铸造及有色合金》2020年第12期1423-1428,共6页Special Casting & Nonferrous Alloys

基　　金：江西省重点研发计划基金资助项目(20192BBEL50002);航空科学基金资助项目(20185456005)。

摘　　要：采用电子束对Ti-48Al-2Nb-2Cr合金进行沉积修复,研究了TiAl金属间化合物电子束修复层的表面成形、显微组织演变。结果表明,Ti-48Al-2Nb-2Cr电子束修复容易产生气孔、裂纹等缺陷;由母材至修复层中心,α2相逐渐增多,γ相逐渐减少。修复层中心区域晶粒内为未转变完全的针状α2/γ相,晶粒边界为块状γm相。近修复层热影响区为细小等轴γ晶粒和α2/γ片层晶团组成的双态组织,近母材热影响区主要由大尺寸的等轴γ晶粒和少量沿晶析出的细条状α2相组成;各区域由于晶粒尺寸及组织上的差异性造成硬度不同,呈现出由焊缝向母材逐渐降低的趋势。修复层中心硬度(HV0.2)最高可达590,平均硬度(HV0.2)约为520,同一区域不同深度硬度差异不明显。The Ti-48Al-2Nb-2Cr alloy was deposited and repaired by electron beam.The surface formation and microstructure evolution of Ti-Al intermetallic compound electron beam repair layer were investigated.The results show that Ti-48Al-2Nb-2Cr electron beam repair is easy to generate defects such as pores and cracks.Theα2 phase is gradually increased and theγphase is gradually decreased from the base material to the center of the repair layer.The grains in the central area of the repair layer are untransformed needle-shapedα2/γphases,and the grain boundaries are massiveγmphases.The heat-affected zone of near-repair layer presents a dual-state structure which are composed of fine equiaxedγgrains andα2/γlamellar clusters.The heat-affected zone in near-base-material is mainly composed of large-sized equiaxedγgrains and a few fine strips along the crystal likeα2phase composition.Due to the diversity of grain size and structure,the microhardness of the alloy at each area is different,presenting a trend of gradually decreasing from the weld to the base material.The center hardness of the repair layer can reach up to 590HV0.2,and the average hardness is about 520HV0.2,and there is no significant difference in hardness at different depths at the same area.

关 键 词：电子束修复 修复层成形 组织转变 显微硬度 

分 类 号：TG456.3[金属学及工艺—焊接] TG146.23[一般工业技术—材料科学与工程]