| LI Song-bai,ZHANG Cheng,LI Xiang,WANG Chong.Effect of Laser Shock Peening on Fatigue Life of 2524 Aluminum Alloy[J],49(5):207-213 |
| Effect of Laser Shock Peening on Fatigue Life of 2524 Aluminum Alloy |
| Received:October 14, 2019 Revised:May 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.05.025 |
| KeyWord:laser shock peening 2524 aluminum alloy residual compressive stress crack growth fatigue life |
| Author | Institution |
| LI Song-bai |
School of Mechanical and Electrical Engineering, Central South University, Changsha , China |
| ZHANG Cheng |
School of Mechanical and Electrical Engineering, Central South University, Changsha , China |
| LI Xiang |
School of Mechanical and Electrical Engineering, Central South University, Changsha , China |
| WANG Chong |
School of Mechanical and Electrical Engineering, Central South University, Changsha , China |
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| Abstract: |
| The work aims to study the influence of laser shock peening (LSP) parameters on the fatigue life of 2524 aluminum alloy. The LSP experiments with different laser energies and different shock times were carried out to test the hardness and the residual stress. Then, the crack propagation experiments and microstructure observations were also conducted. LSP treatment could significantly improve the surface hardness of the material, and the hardness value of the material increased with the increasing of the shock energy and the shock times, but the hardness growth rate decreased with the increasing of the shock times. In addition, LSP treatment formed a large residual compressive stress on the surface of the specimen. Under one shock with laser energy of 6.25 J, the maximum residual compressive stress was -222 MPa. Furthermore, the residual compressive stress increased with the increasing laser energy and shock times. However, there was a threshold for shock times. Compared with the unshocked specimen, the fatigue life of the one-shock specimen and two-shock specimen increased by 32% and 41%, respectively. The microscopic morphology of the fracture of the specimen was observed. In the position with 28 mm crack, the fatigue strip spacing of the unshocked specimen, one-shock specimen and two-shock specimen was 1.06, 0.628 and 0.488 μm, respectively. The crack growth rates were 1.06×10-3, 6.28×10-4 and 4.88×10-4 mm/N, respectively. LSP can significantly improve the surface hardness of 2524 aluminum alloy and produce large residual compressive stress on the surface. LSP can effectively delay the fatigue crack growth rate of 2524 aluminum alloy, thus extending the fatigue life. |
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