Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 Alloy
Micro-shot peening under two Almen intensities was performed to increase the fatigue endurance limit of anodized AA 7075 alloy in T6 condition. Compressive residual stress (CRS) and a nano-grained structure were present in the outermost as-peened layer. Microcracks in the anodized layer obviously ab...
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MDPI AG
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| author | Chih-Hang Su Tai-Cheng Chen Yi-Shiun Ding Guan-Xun Lu Leu-Wen Tsay |
| author_facet | Chih-Hang Su Tai-Cheng Chen Yi-Shiun Ding Guan-Xun Lu Leu-Wen Tsay |
| author_sort | Chih-Hang Su |
| collection | DOAJ |
| description | Micro-shot peening under two Almen intensities was performed to increase the fatigue endurance limit of anodized AA 7075 alloy in T6 condition. Compressive residual stress (CRS) and a nano-grained structure were present in the outermost as-peened layer. Microcracks in the anodized layer obviously abbreviated the fatigue strength/life of the substrate. The endurance limit of the anodized AA 7075 was lowered to less than 200 MPa. By contrast, micro-shot peening increased the endurance limit of the anodized AA 7075 to above that of the substrate (about 300 MPa). Without anodization, the fatigue strength of the high peened (HP) specimen fluctuated; this was the result of high surface roughness of the specimen, as compared to that of the low peened (LP) one. Pickling before anodizing was found to erode the outermost peened layer, which caused a decrease in the positive effect of peening. After anodization, the HP sample had a greater fatigue strength/endurance limit than that of the LP one. The fracture appearance of an anodized fatigued sample showed an observable ring of brittle fracture. Fatigue cracks present in the brittle coating propagated directly into the substrate, significantly damaging the fatigue performance of the anodized sample. The CRS and the nano-grained structure beneath the anodized layer accounted for a noticeable increase in resistance to fatigue failure of the anodized micro-shot peened specimen. |
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| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-11T09:35:21Z |
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| spelling | doaj.art-3bac02d523cf4c808ebf7298e7a6844b2023-11-16T17:17:59ZengMDPI AGMaterials1996-19442023-01-01163116010.3390/ma16031160Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 AlloyChih-Hang Su0Tai-Cheng Chen1Yi-Shiun Ding2Guan-Xun Lu3Leu-Wen Tsay4Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung 20224, TaiwanNuclear Fuels and Materials Division, Institute of Nuclear Energy Research, Taoyuan 32546, TaiwanMaterial Research Group, Asia Development Center, SRAM LLC, Taichung 40765, TaiwanDepartment of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung 20224, TaiwanDepartment of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung 20224, TaiwanMicro-shot peening under two Almen intensities was performed to increase the fatigue endurance limit of anodized AA 7075 alloy in T6 condition. Compressive residual stress (CRS) and a nano-grained structure were present in the outermost as-peened layer. Microcracks in the anodized layer obviously abbreviated the fatigue strength/life of the substrate. The endurance limit of the anodized AA 7075 was lowered to less than 200 MPa. By contrast, micro-shot peening increased the endurance limit of the anodized AA 7075 to above that of the substrate (about 300 MPa). Without anodization, the fatigue strength of the high peened (HP) specimen fluctuated; this was the result of high surface roughness of the specimen, as compared to that of the low peened (LP) one. Pickling before anodizing was found to erode the outermost peened layer, which caused a decrease in the positive effect of peening. After anodization, the HP sample had a greater fatigue strength/endurance limit than that of the LP one. The fracture appearance of an anodized fatigued sample showed an observable ring of brittle fracture. Fatigue cracks present in the brittle coating propagated directly into the substrate, significantly damaging the fatigue performance of the anodized sample. The CRS and the nano-grained structure beneath the anodized layer accounted for a noticeable increase in resistance to fatigue failure of the anodized micro-shot peened specimen.https://www.mdpi.com/1996-1944/16/3/1160AA 7075-T6 alloyanodizingmicro-shot peeningnanograinrotating bending fatigue |
| spellingShingle | Chih-Hang Su Tai-Cheng Chen Yi-Shiun Ding Guan-Xun Lu Leu-Wen Tsay Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 Alloy Materials AA 7075-T6 alloy anodizing micro-shot peening nanograin rotating bending fatigue |
| title | Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 Alloy |
| title_full | Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 Alloy |
| title_fullStr | Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 Alloy |
| title_full_unstemmed | Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 Alloy |
| title_short | Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 Alloy |
| title_sort | effects of micro shot peening on the fatigue strength of anodized 7075 t6 alloy |
| topic | AA 7075-T6 alloy anodizing micro-shot peening nanograin rotating bending fatigue |
| url | https://www.mdpi.com/1996-1944/16/3/1160 |
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