采用搅拌摩擦焊方法对5083铝合金进行搭接实验。用万能试验机对接头进行拉剪试验，对其断口利用SEM电镜进行观察和分析，并使用光学显微镜对其接头横截面进行组织观察。结果表明：即使搅拌针长度短于上层铝板的厚度，上、下层铝板在搅拌针作用的区域，晶粒都发生了一定细化，其尺寸都小于母材。而且焊缝横截面的显微硬度分布也显示出两板在搅拌针作用区域的硬度均与母材相当。在拉剪试验时，界面结合处没有出现断裂现象，断裂位置均在上层铝板前进侧的热影响区。接头强度系数最高可达80%，接头的断裂形式为韧性断裂。
Abstract
Aluminum alloy 5083 was welded by friction stir lap welding in the test. The tensile-shear test of the lap joints was tested by universal testing machine and the fracture behavior of the joint was examined by scanning electron microscopy, microstructures of the joint were investigated by optical microscope. The results showed that microstructure of the upper and lower in the zone of the tool were refined, although the length of the pin was shorter than the upper sheet. And micro-hardness showed that the hardness of the zone of the pin approached to the hardness of base metal. In the tensile-shear test, the interface didn’t fracture, but fracture location exists in the HAZ of the upper sheet. The joint strength constant can reach about 80% of the base metal. Fractographs confirm that the fracture of the joint is the mode of ductile fracture.
关键词
搅拌摩擦焊 /
搭接 /
铝合金 /
力学性能 /
韧性断裂
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Key words
friction stir welding /
lap joint /
aluminum alloy /
mechanical property /
ductile fracture
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参考文献
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