TiAl/Ti60电子束焊接接头组织及性能

对 TiAl/Ti60 异种材料进行电子束焊接,研究了其接头成形特点、焊缝组织、热影响区组织及接头力学性能.结果表明,TiAl/Ti60 电子束焊接时,接头的主要缺陷是存在宏观横向裂纹.焊缝组织快速冷却时主要形成的马氏体组织为针片状的α2 相,Ti60侧热影响区为针状α' 相,TiAl 侧热影响区为马氏体形貌.接头焊缝区硬度值较大,且熔合线两侧的硬度分布梯度较大.TiAl/Ti60 常规电子束焊接接头,接头的抗拉强度最大可达到 175.4 MPa,接头强度相对较低.拉伸断裂发生在 TiAl 侧熔合线附近,断裂为脆性断裂,断裂特征为穿晶断裂.

Abstract：

Electron beam welding experiments of TiAl/Ti60dissimilar joints were carried out. Microstructure and mechanical properties were studied. The results show that major defect in TiAl/Ti60 joint during electron beam welding is transverse crack. Weld zone is characterized by acicular α2 plates, HAZ near to Ti60 by acicular α' phase, and HAZ near to TiAl by martensite. Hardness in weld zone is relatively higher, as well as the hardness gradient along fusion line. Fracture during stretching occurs in the region near fusion line. Fracture mode is brittle fracture, which is characterized by transgranular fracture.