异质钛合金线性摩擦焊接头微观组织

Microstructure in linear friction welded dissimillar titanium alloy joint

为了探明TC11与TC17异质钛合金线性摩擦焊接头微观组织形成机制,采用光学显微镜和扫描电镜研究接头不同区域的微观组织.结果表明,线性摩擦焊接头由TC11一侧的热力影响区(TMAZ)、TC11一侧的焊缝区、TC17一侧的焊缝区和TC17一侧的TMAZ所组成.在TMAZ未发现有动态再结晶发生,而材料的相变与变形是同时进行的.在焊缝区内发生了动态再结晶过程,摩擦停止后在摩擦界面上形成初生β共生晶粒.在振幅为3 mm、频率为40 Hz、摩擦压力为66.7 MPa条件下,随着摩擦时间的延长,初生β相动态再结晶晶粒尺寸和α相片层宽度增加.

Microstructure at the different zones of linear friction welded TC11 and TC17 dissimillar titanium alloy joint were investigated to understand the mechanism of microstructural formation in the joints.The results showed that four different structures existed in linear friction welded joint,i.e.thermomechanically affected zone(TMAZ) in the region close to TC11 parent material,TMAZ the region close to TC17 parent material,weld zone in the region close to TC11 TMAZ,and weld zone in the region close to TC17 TMAZ.Although no dynamic recrystallization was observed in the TMAZ,the phase transformation would occur concurrently with material deformation during welding.In contrast,dynamic recrystallization occurred in the weld.Common prior-beta grains were formed at the original rubbing interface after welding.Under the conditions of 3 mm amplitude of oscillation,40 Hz frequency of oscillation,66.7 MPa friction pressure and absence of forge force,prior-beta grain size and alpha plate width increased with friction time increasing.