(大連理工大學 精密與特種加工教育部重點實驗室，大連 116024)
摘 要: 對0.5 mm厚Hastelloy C-276薄板激光焊接接頭進行疲勞試驗，結合應力-壽命(S-N)曲線和疲勞斷口形貌，研究母材及焊接接頭的疲勞性能，分析母材和焊接接頭的疲勞斷裂機理。結果表明：0.5 mm Hastelloy C-276薄板焊接接頭和母材的S-N曲線斜率基本相同，焊接接頭疲勞性能和母材的基本相當；母材疲勞斷口疲勞裂紋起源于試樣側表面，主要沿寬度方向擴展，隨著應力的減小，疲勞源數(shù)目減少，疲勞裂紋擴展速率減小；焊接接頭在母材和焊縫處隨機斷裂，焊接接頭母材區(qū)斷口形貌和母材斷口形貌基本一致，而焊接接頭焊縫區(qū)斷口的疲勞裂紋起源于側表面棱角處和焊縫表面，焊縫表面是主要疲勞源，裂紋主要沿厚度方向進行擴展，疲勞裂紋擴展區(qū)呈現(xiàn)出準解理斷裂特征。
關鍵字: Hastelloy C-276；激光焊接；薄板；疲勞性能
（Key Laboratory for Precision and Non-traditional Machining Technology, Ministry of Education, Dalian University of Technology, Dalian 116024, China）
Abstract:Fatigue test was conducted on the laser welded joints of 0.5 mm thick Hastelloy C-276 thin sheet. The fatigue properties and fatigue fracture mechanism were investigated by S-N curves and fatigue fracture morphology of the base metal and the weld joint. The results show that the slopes of S-N curves of the laser welded joints and base metal are basically the same and the fatigue properties of the laser welded joints are almost equal to those of the base metal. The fatigue crack of base metal originates from the side surface of samples and propagates along the width direction of fatigue fracture. As the stress decreases, the number of fatigue sources decreases, and the fatigue crack growth rate also decreases. Fatigue fractures of laser welded joints distribute in the base metal and the weld zone randomly, and the fatigue fracture macro morphology of the weld joint fractured in the base metal is basically identical to that of the base metal. The fatigue crack of weld joint fractured in the weld zone originates from the edge of side surface and the weld surface, the latter is the main fatigue source. The crack propagates along the thickness direction of fatigue fracture. Fatigue crack propagation area of the weld zone fracture presents quasi-cleavage fracture.
Key words: Hastelloy C-276; laser welding; thin sheet; fatigue property
