GH80A镍合金电子束焊接接头旋转弯曲-工程科学与技术.docVIP

GH80A镍合金电子束焊接接头旋转弯曲 高周疲劳行为研究 张 宏，李久楷，刘永杰，王清远＊ (四川大学610065) 摘要：)曲线和疲劳断口，同时利用扫描电镜（Scanning Electron Microscope,SEM）)母材和电子束焊接接头应力-寿命(S-N)曲线分布趋势一致，但焊接接头疲劳强度要低于母材，在靠近107周次时两者疲劳强度差距最小)在高应力幅（低周疲劳寿命阶段）母材和焊接接头的疲劳裂纹均起源于试件表面并且都是多点萌生断裂，焊接接头疲劳断口位置位于焊接熔合区或热影响区；3)在低应力幅（高周疲劳寿命阶段）疲劳裂纹在试件次表面萌生，焊接接头疲劳断口位于热影响区或焊接母材靠近热影响区处；4) 通过有限元模拟发现微裂纹的存在裂纹扩展 关键字GH80A；电子束焊接接头；旋转弯曲疲劳；热影响区；有限元 Research on Rotary Bending High Cycle Fatigue Behavior of the Electron Beam Welding joint for GH80A Nickel Alloy Zhang Hong，Li Jiukai，Liu Yongjie，Wang Qingyuan （Failure Mechanics and Engineering Disaster Prevention and Mitigation Key Laboratory of Sichuan Province, Sichuan Univ, Chengdu 610065, China) With the application of nickel alloy electron beam welding in industry, especially in critical long service equipment such as aircraft engine and gas turbines etc., it is necessary to systematically analyze and study the high cycle fatigue properties and fracture mechanism of nickel alloy electron beam welding joint. Fatigue tests were carried out using the rotary bending high cycle fatigue testing machine. The stress-life (S-N) curves and fatigue fracture of the base metal and welded joints were obtained from experiment. Then, the fatigue fracture surfaces were examined by scanning electron microscope (SEM). The fatigue crack initiation and extension zones of the base metal and welded joints under different stress amplitude were analyzed and determined, which the crack initiation location was affected by the stress amplitude. Finally, the effect of the location and size of microcracks on the fatigue properties of the welded joint was discussed by the finite element method (FEM). The experimental and simulation results show that: 1) the stress-life (S-N) curves distribution trend of the base metal and welded joints is consistent, and fatigue strength of the welded joint is lower than the base metal, which there is small difference nearby the 107 cycle; 2) with the high stress amplitude (low cycle fatigue life sta