| 摘要: |
| 文中对超声冲击处理前后的7A52铝合金焊接接头显微组织、显微硬度以及残余应力进行了分析，并对超声冲击处理前后的接头在不同循环应力比的加载条件下进行了疲劳试验.结果表明，经超声冲击处理后接头塑性变形层厚度在45~70 μm左右，母材区表面硬度提高了170%，焊缝区硬度提高了大约70%，改变了焊态残余应力分布，成功引入了压应力；在疲劳试验中，循环次数为2×106的条件下，加载应力循环比为0.1时，冲击态接头的疲劳强度为60.26 MPa，比疲劳强度为40.74 MPa的焊态试样提高了47.9%，而在加载应力循环比为0.45时，冲击态接头的疲劳强度为46.53 MPa，比疲劳强度为39.97 MPa的焊态试样提高了16.4%. |
| 关键词: 超声冲击处理 7A52铝合金 焊接接头 疲劳强度 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（51165026）；内蒙古自治区自然科学基金资助项目（2015MS0537） |
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| Effect on the fatigue properties of 7A52 aluminum alloy welded joint by ultrasonic impact |
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XIE Ruijun, CHEN Furong, TANG Dafu, CHEN Chao
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School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051, China
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| Abstract: |
| In this paper, the microstructure, microhardness, residual stress and fatigue test of ultrasonic impact before and after the processing of 7A52 aluminum alloy welded joint were analyzed. The results showed that joint plastic deformation layer thickness was about 45 to 70 μm, base metal hardness increased by 170%, weld surface hardness increased by 70%, after ultrasonic impact treatment. In fatigue tests, when the cycles were 2×106 times, the loading stress cycle ratio was 0.1, the fatigue strength of the impact of state joint was 60.26 MPa, increased by 47.9% than the welded specimen fatigue strength was 40.74%. In the loading cycle stress ratio was 0.45, the fatigue strength of the impact of state joint was 46.53 MPa, increased by 16.4% than the welded specimen fatigue strength is 39.97 MPa. |
| Key words: ultrasonic impact treatment 7A52 aluminum alloy welded joint fatigue strength |
