(华中科技大学 材料成形与模具技术国家重点实验室，武汉430074)
摘 要: 采用一种水平切取疲劳试样的方法，研究厚板TA15合金电子束焊接接头的焊缝(WS)和热影响区(HAZ)的显微组织、硬度、疲劳裂纹扩展速率以及疲劳断口形貌。结果表明：在距焊缝顶端同样高度时，热影响区的组织不均匀性最大；从焊缝顶端到底部，焊缝的α′马氏体组织细化，但焊缝的组织不均匀性增大；受较高的组织不均匀性的影响，热影响区的疲劳裂纹扩展速率比焊缝的高，疲劳断口形貌反映了这种宏观上的差别。
关键字: TA15钛合金；电子束焊接；组织不均匀性；疲劳裂纹扩展；疲劳断口形貌
fatigue crack growth of TA15 electron beam welded joint
（State Key Laboratory of Material Processing and Die & Mould Technology,
Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:By a means of horizontally intercepting fatigue specimen, the microstructure, hardness, fatigue crack growth rate and fatigue fractograph in the welding seam (WS) and heat-affected zone (HAZ) of thick TA15 alloy electron beam (EB) welded joint were studied. The results indicate that on the same height from the top of WS, the microstructure heterogeneity is the most severe in HAZ, from the top to root of WS, the microstructure heterogeneity increases with decreasing α′ martensite size. Attributed primarily to the effect of microstructure heterogeneity, the fatigue crack growth rate (FCGR) is faster in HAZ than that in WS. The fatigue fractographs show this macroscopical difference by scanning electron microscopy (SEM) analyses.
Key words: TA15 titanium; electron beam weld (EBW); microstructure heterogeneity; fatigue crack growth; fatigue fractograph
