| 摘要: |
| 为研究回填时间对回填式搅拌摩擦点焊接头断裂模式和断裂机理的影响，对上下板厚度分别为1.5 mm和2 mm的LY12铝合金板材进行了点焊试验，并对焊后接头进行拉剪试验.结果表明，当回填时间较短时，套筒作用区与热力影响区间界面上的原子扩散效果差，甚至在近表面附近出现开裂，导致接头的剪切-塞型断裂.当回填时间足够长时，焊接接头的断裂模式转化为剪切断裂，裂纹主要沿着上下板搭接面扩展.同时，显微结构、硬度与断口形貌的试验结果验证了文中对断裂机制的解释. |
| 关键词: 回填式搅拌摩擦点焊 LY12铝合金 回填时间 断裂 |
| DOI：10.12073/j.hjxb.20170509 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（51204111）；辽宁省自然科学基金资助项目（2014024008） |
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| Effect of refill time on fracture feature of refill friction stir spot welding |
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JI Shude1, WANG Yue1, MA Lin1, CHAI Peng2, GAO Shuangsheng1
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1.Faculty of Aerospace Engineering, Shenyang Aerospace University, Shenyang 110136, China;2.School of Mechanical Engineering & Automation, Beihang University, Beijing 100191, China
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| Abstract: |
| In order to investigate the effect of refill time on fracture mode and fracture mechanism on refill friction stir spot welding (RFSSW), the LY12 aluminum alloy plates with the thickness of 1.5 mm and 2.0 mm were welded and then the tensile-shear experiments were performed. Under shorter refill time, the atom diffusion effect at the interface between sleeve stir zone and thermo-mechanically affected zone is poor and the crack may appear near the top surface of upper plate, which results in the shear-plug fracture mode. When the refill time is long enough, the crack mainly propagates along the interface between the upper and lower plates, which causes the shear fracture of RFSSW joint. Moreover, microstructure, microhardness and fracture morphology can all verify the illustration about the fracture mechanism of RFSSW joint. |
| Key words: refill friction stir spot welding LY12 aluminum alloy refill time fracture |
