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研究了5052-H34铝合金搅拌摩擦焊缝的疲劳裂纹萌发及扩展机制。采用光学显微镜和扫描电镜分析焊缝材料的显微组织,使用疲劳拉伸方法测试焊缝试样的力学性能。结果表明,经疲劳拉伸试验,母材和热影响区裂缝周围出现滑移带,而搅拌区的裂缝附近滑移带却不明显。母材的疲劳裂缝传播速度比搅拌区快,但比热影响区传播的慢,测得焊缝的疲劳寿命达到了母材的80.3%。
The fatigue crack growth and propagation mechanism of 5052-H34 aluminum alloy friction stir weld was studied. The microstructure of the weld material was analyzed by optical microscope and scanning electron microscope, and the mechanical properties of the weld specimen were tested by fatigue drawing method. The results show that the slip zone appears around the cracks in the base metal and the heat affected zone after fatigue testing, while the slip zone near the crack in the stirred zone is not obvious. The propagation velocity of fatigue crack of base metal was faster than that of stirring zone, but slower than that of heat affected zone. The fatigue life of weld metal was measured to reach 80.3% of base metal.