Ti6242合金线性摩擦焊及焊后热处理接头显微组织与力学性能的多尺度表征

Multi-scale characterizations of microstructure andmechanical properties of Ti6242 alloy linear friction welded joint with post-welded heat treatment

通过线性摩擦焊技术对一种近α钛合金(Ti6242)进行连接,并进行焊后热处理。为了研究显微组织演变并建立显微组织与接头力学性能的关系,对焊态与焊后热处理的两种接头进行多尺度表征。结果表明,两种接头的断裂位置均位于母材,而经焊后热处理的接头在焊缝与热力影响区的硬度进一步提升。经过热处理后焊缝处的等轴晶粒中产生薄片状的α相集束,而热力影响区处的马氏体相分解为(α+β)相,从而提高焊接接头处的硬度。

A nearαtitanium alloy(Ti6242)was joined by the linear friction welding technique followed by the post-welded heat treatment(PWHT).Both joints in as-welded and PWHTed conditions were characterized in a multi-scale manner to investigate the evolution of microstructure and establish the relationship between the microstructure and mechanical properties of the joints.Results show that both joints fail in the base material,while the PWHTed joints havelarge hardness enhancement in the welding line(WL)and thermo-mechanically affected zone(TMAZ).After heat treatment,the cluster of the flakierαphaseis formed inside the equiaxed grains in WL,while the martensite phase in TMAZ is decomposed into the(α+β)phase,both of which can improve the hardness of the joint.