Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint
Very high cycle fatigue behavior of nugget zone in AA 7075 friction stir welded joint was experimentally investigated using ultrasonic fatigue testing system (20 kHz) to clarify the crack initiation mechanism. It was found that the fatigue strength of nugget zone decreased continuously even beyond 1...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2017-01-01
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| Series: | Advances in Materials Science and Engineering |
| Online Access: | http://dx.doi.org/10.1155/2017/7189369 |
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| author | Chao He Kazuhiro Kitamura Kun Yang Yong-jie Liu Qing-yuan Wang Qiang Chen |
| author_facet | Chao He Kazuhiro Kitamura Kun Yang Yong-jie Liu Qing-yuan Wang Qiang Chen |
| author_sort | Chao He |
| collection | DOAJ |
| description | Very high cycle fatigue behavior of nugget zone in AA 7075 friction stir welded joint was experimentally investigated using ultrasonic fatigue testing system (20 kHz) to clarify the crack initiation mechanism. It was found that the fatigue strength of nugget zone decreased continuously even beyond 107 cycles with no traditional fatigue limits. Fatigue cracks initiated from the welding defects located at the bottom side of the friction stir weld. Moreover, a special semicircular zone could be characterized around the crack initiation site, of which the stress intensity factor approximately equaled the threshold of fatigue crack propagation rate. Finally, a simplified model was proposed to estimate the fatigue life by correlating the welding defect size and applied stress. The predicted results are in good agreement with the experimental results. |
| format | Article |
| id | doaj-art-73bb8aae2550408fa35cffa21db569ac |
| institution | Kabale University |
| issn | 1687-8434 1687-8442 |
| language | English |
| publishDate | 2017-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Materials Science and Engineering |
| spelling | doaj-art-73bb8aae2550408fa35cffa21db569ac2025-02-03T01:01:46ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422017-01-01201710.1155/2017/71893697189369Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded JointChao He0Kazuhiro Kitamura1Kun Yang2Yong-jie Liu3Qing-yuan Wang4Qiang Chen5School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, ChinaDepartment of Mechanical Engineering, Kochi National College of Technology, Nankoku 783-8508, JapanKey Laboratory of Energy Engineering Safety and Disaster Mechanics, Ministry of Education, Sichuan University, Chengdu 610065, ChinaKey Laboratory of Energy Engineering Safety and Disaster Mechanics, Ministry of Education, Sichuan University, Chengdu 610065, ChinaSchool of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, ChinaMicromechanics Laboratory, Faculty of Engineering, Kyushu University, Fukuoka 8190395, JapanVery high cycle fatigue behavior of nugget zone in AA 7075 friction stir welded joint was experimentally investigated using ultrasonic fatigue testing system (20 kHz) to clarify the crack initiation mechanism. It was found that the fatigue strength of nugget zone decreased continuously even beyond 107 cycles with no traditional fatigue limits. Fatigue cracks initiated from the welding defects located at the bottom side of the friction stir weld. Moreover, a special semicircular zone could be characterized around the crack initiation site, of which the stress intensity factor approximately equaled the threshold of fatigue crack propagation rate. Finally, a simplified model was proposed to estimate the fatigue life by correlating the welding defect size and applied stress. The predicted results are in good agreement with the experimental results.http://dx.doi.org/10.1155/2017/7189369 |
| spellingShingle | Chao He Kazuhiro Kitamura Kun Yang Yong-jie Liu Qing-yuan Wang Qiang Chen Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint Advances in Materials Science and Engineering |
| title | Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint |
| title_full | Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint |
| title_fullStr | Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint |
| title_full_unstemmed | Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint |
| title_short | Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint |
| title_sort | very high cycle fatigue crack initiation mechanism in nugget zone of aa 7075 friction stir welded joint |
| url | http://dx.doi.org/10.1155/2017/7189369 |
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