| DING Ya-ru,CHEN Fu-rong.Effect of A-UIT on the Friction and Wear Properties of 7075 Aluminum Alloy Laser Welded Joint[J],50(4):235-243 |
| Effect of A-UIT on the Friction and Wear Properties of 7075 Aluminum Alloy Laser Welded Joint |
| Received:October 31, 2020 Revised:March 18, 2021 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2021.04.023 |
| KeyWord:aging-ultrasonic impact composite treatment roughness nanocrystalline wear coefficient laser welding wear rate |
| Author | Institution |
| DING Ya-ru |
School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot , China;Inner Mongolia Technical College of Mechanics and Electrics, Hohhot , China |
| CHEN Fu-rong |
School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot , China |
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| Abstract: |
| The work aims to study the effect of aging-ultrasonic impact composite treatment (A-UIT) on the wear properties of laser welding of aluminum alloy. The method is to treat the laser weld of 7075 aluminum alloy by aging treatment, ultrasonic impact treatment and A-UIT composite treatment. The surface hardness, the surface roughness, the 3D morphology and the scanning microstructure of the weld were compared after aging treatment, ultrasonic impact treatment and A-UIT composite treatment. The effect and mechanism of A-UIT composite treatment, aging treatment and ultrasonic impact treatment on the wear resistance of weld are analyzed. The results show that the roughness of the weld treated by ultrasonic impact is 8.65 μm smaller than that of the untreated weld, the surface hardness of the weld treated by ultrasonic impact is 47HV higher than that of the untreated weld, the friction coefficient of the weld treated by ultrasonic impact is 0.17 lower than that of the untreated weld, and the wear rate of the weld treated by ultrasonic impact is 70% lower than that of the untreated weld. After 6, 24 and 32 h aging treatment, the roughness is 10.18, 4.19 and 5.88 μm smaller than the welding. The surface hardness is 37, 55 and 44 HV higher than the welding. The average wear coefficient is 0.10, 0.08 and 0.09 lower than the welding. The wear rate is 51%, 54% and 61% lower than the welding. Compared with the aging treatment of 6, 24 and 32 hours, the roughness of A-UIT composite treatment is 9.88, 10.58 and 8.7 μm smaller, the surface hardness is 43, 44 and 31HV higher, the average friction coefficient is 0.1, 0.1 and 0.07 lower, and the wear rate is 35%, 41% and 27% lower. The wear of A-UIT composite treatment weld is mainly abrasive wear, and there is local delamination wear. The single aging treatment weld is mainly light color delamination wear, and there is a small amount of abrasive wear, with large wear area and a small amount of oxidation wear. Both the aging treatment and UIT can effectively improve the wear resistance of the laser weld of 7075 aluminum alloy. The UIT is more effective than aging treatment, the wear coefficient of the UIT is 15.3% smaller than the 24 h aging treatment, and the wear rate is 36.1% of the aging treatment. Due to the joint action of nanocrystals and aging intensification phase, the effect of UIT on wear resistance is more obvious than that of aging treatment and UIT. The wear coefficient with 24 h A-UIT is 28.5% higher than 24 h aging treatment, 8.6% higher than UIT. The wear rate with 24 h A-UIT is 40.9% higher than 24 h aging treatment, 76.9% higher than UIT. |
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