(華中科技大學(xué) 材料成形與模具技術(shù)國家重點實驗室，武漢430074)
摘 要: 采用一種水平切取疲勞試樣的方法，研究厚板TA15合金電子束焊接接頭的焊縫(WS)和熱影響區(qū)(HAZ)的顯微組織、硬度、疲勞裂紋擴展速率以及疲勞斷口形貌。結(jié)果表明：在距焊縫頂端同樣高度時，熱影響區(qū)的組織不均勻性最大；從焊縫頂端到底部，焊縫的α′馬氏體組織細化，但焊縫的組織不均勻性增大；受較高的組織不均勻性的影響，熱影響區(qū)的疲勞裂紋擴展速率比焊縫的高，疲勞斷口形貌反映了這種宏觀上的差別。
關(guān)鍵字: TA15鈦合金；電子束焊接；組織不均勻性；疲勞裂紋擴展；疲勞斷口形貌
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
