TiAl/Ti60电子束焊接接头组织及性能

Microstructure and mechanical properties of electron beam welded dissimilar TiAl/Ti60 joint

摘要: 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/Ti60 dissimilar 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.