TC4-DT钛合金电子束焊接接头疲劳断裂过程的原位观测

In-stiu Observation of Fatigue Fracture Course of TC4-DT Electron Beam Welded Joints

通过对TC4-DT钛合金焊接接头显微组织的观察和疲劳断裂过程的原位观测,分析了焊接接头的显微组织特征,研究了焊接接头的疲劳裂纹萌生与扩展行为。结果表明:TC4-DT焊接接头疲劳断裂于母材区,疲劳裂纹萌生于试样的边缘,裂纹既可以沿着初生α相扩展又能直接切过初生α相扩展,裂纹的萌生寿命占整个疲劳寿命的比例较大,裂纹的扩展寿命很短。

By the microstructure observation and the in-stiu observation of the fatigue fracture course of TC4-DT titanium alloy welded joints, the microstructure characteristic of the welded joints was analyzed. The behavior of fatigue crack initiation and propagation was investigated. The results show that the welded joint fractures in base metal. The fatigue crack initiates at the edge of the specimen. The crack is propagated either along the primary α phase or directly through the primary α phase. The crack initiation life takes a large proportion of total fatigue life, and the crack propagation life is very short