Influence of Retrogression Time on the Fatigue Crack Growth Behavior of a Modified AA7475 Aluminum Alloy
This paper investigates the effect of retrogression time on the fatigue crack growth of a modified AA7475 aluminum alloy. Tests including tensile strength, fracture toughness, and fatigue limits were performed to understand the changes in properties with different retrogression procedures at 180 °C....
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MDPI AG
2023-03-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/16/7/2733 |
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| author | Xu Zheng Yi Yang Jianguo Tang Baoshuai Han Yanjin Xu Yuansong Zeng Yong Zhang |
| author_facet | Xu Zheng Yi Yang Jianguo Tang Baoshuai Han Yanjin Xu Yuansong Zeng Yong Zhang |
| author_sort | Xu Zheng |
| collection | DOAJ |
| description | This paper investigates the effect of retrogression time on the fatigue crack growth of a modified AA7475 aluminum alloy. Tests including tensile strength, fracture toughness, and fatigue limits were performed to understand the changes in properties with different retrogression procedures at 180 °C. The microstructure was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The findings indicated that as the retrogression time increased, the yield strength decreased from 508 MPa to 461 MPa, whereas the fracture toughness increased from 48 MPa√m to 63.5 MPa√m. The highest fracture toughness of 63.5 MPa√m was seen after 5 h of retrogression. The measured diameter of η’ precipitates increased from 6.13 nm at the retrogression 1 h condition to 6.50 nm at the retrogression 5 h condition. Prolonged retrogression also increased the chance of crack initiation, with slower crack growth rate in the long transverse direction compared to the longitudinal direction. An empirical relationship was established between fracture toughness and the volume fraction of age-hardening precipitates, with increasing number density of precipitates seen with increasing retrogression time. |
| first_indexed | 2024-03-11T05:32:21Z |
| format | Article |
| id | doaj.art-f9d0beb2572b4d8ead3e0273823ff9be |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-11T05:32:21Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-f9d0beb2572b4d8ead3e0273823ff9be2023-11-17T17:04:19ZengMDPI AGMaterials1996-19442023-03-01167273310.3390/ma16072733Influence of Retrogression Time on the Fatigue Crack Growth Behavior of a Modified AA7475 Aluminum AlloyXu Zheng0Yi Yang1Jianguo Tang2Baoshuai Han3Yanjin Xu4Yuansong Zeng5Yong Zhang6School of Materials Science and Engineering, Central South University, Changsha 410083, ChinaShanxi Aircraft Industry Corporation, Ltd., Hanzhong 723213, ChinaSchool of Materials Science and Engineering, Central South University, Changsha 410083, ChinaAVIC Manufacturing Technology Institute, Beijing 100024, ChinaAVIC Manufacturing Technology Institute, Beijing 100024, ChinaAVIC Manufacturing Technology Institute, Beijing 100024, ChinaSchool of Materials Science and Engineering, Central South University, Changsha 410083, ChinaThis paper investigates the effect of retrogression time on the fatigue crack growth of a modified AA7475 aluminum alloy. Tests including tensile strength, fracture toughness, and fatigue limits were performed to understand the changes in properties with different retrogression procedures at 180 °C. The microstructure was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The findings indicated that as the retrogression time increased, the yield strength decreased from 508 MPa to 461 MPa, whereas the fracture toughness increased from 48 MPa√m to 63.5 MPa√m. The highest fracture toughness of 63.5 MPa√m was seen after 5 h of retrogression. The measured diameter of η’ precipitates increased from 6.13 nm at the retrogression 1 h condition to 6.50 nm at the retrogression 5 h condition. Prolonged retrogression also increased the chance of crack initiation, with slower crack growth rate in the long transverse direction compared to the longitudinal direction. An empirical relationship was established between fracture toughness and the volume fraction of age-hardening precipitates, with increasing number density of precipitates seen with increasing retrogression time.https://www.mdpi.com/1996-1944/16/7/2733retrogression and re-ageingAl-Zn-Mg alloysfatigue crack growthη’ precipitatesAA7475 aluminum alloy |
| spellingShingle | Xu Zheng Yi Yang Jianguo Tang Baoshuai Han Yanjin Xu Yuansong Zeng Yong Zhang Influence of Retrogression Time on the Fatigue Crack Growth Behavior of a Modified AA7475 Aluminum Alloy Materials retrogression and re-ageing Al-Zn-Mg alloys fatigue crack growth η’ precipitates AA7475 aluminum alloy |
| title | Influence of Retrogression Time on the Fatigue Crack Growth Behavior of a Modified AA7475 Aluminum Alloy |
| title_full | Influence of Retrogression Time on the Fatigue Crack Growth Behavior of a Modified AA7475 Aluminum Alloy |
| title_fullStr | Influence of Retrogression Time on the Fatigue Crack Growth Behavior of a Modified AA7475 Aluminum Alloy |
| title_full_unstemmed | Influence of Retrogression Time on the Fatigue Crack Growth Behavior of a Modified AA7475 Aluminum Alloy |
| title_short | Influence of Retrogression Time on the Fatigue Crack Growth Behavior of a Modified AA7475 Aluminum Alloy |
| title_sort | influence of retrogression time on the fatigue crack growth behavior of a modified aa7475 aluminum alloy |
| topic | retrogression and re-ageing Al-Zn-Mg alloys fatigue crack growth η’ precipitates AA7475 aluminum alloy |
| url | https://www.mdpi.com/1996-1944/16/7/2733 |
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