| HUANG Hao,NIU Jintao,YIN Jianguo,ZHANG Chaoyang,WANG Xiangyu,QIAO Yang.Surface Integrity and Corrosion Resistance of 2A97 Al-Li Alloy after Shot Peening[J],53(15):184-193 |
| Surface Integrity and Corrosion Resistance of 2A97 Al-Li Alloy after Shot Peening |
| Received:August 07, 2023 Revised:November 15, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.15.017 |
| KeyWord:2A97 Al-Li alloy shot peening process surface integrity corrosion resistance wettability |
| Author | Institution |
| HUANG Hao |
School of Mechanical Engineering, University of Jinan, Jinan , China |
| NIU Jintao |
School of Mechanical Engineering, University of Jinan, Jinan , China;Shandong Kaitai Shot Blasting Machinery Co., Ltd., Shandong Binzhou , China |
| YIN Jianguo |
Shandong Kaitai Shot Blasting Machinery Co., Ltd., Shandong Binzhou , China |
| ZHANG Chaoyang |
Shandong Kaitai Shot Blasting Machinery Co., Ltd., Shandong Binzhou , China |
| WANG Xiangyu |
School of Mechanical Engineering, University of Jinan, Jinan , China |
| QIAO Yang |
School of Mechanical Engineering, University of Jinan, Jinan , China |
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| Abstract: |
| Due to the strong activity of Li element metal, Al-Li alloy is more vulnerable to the corrosion of harsh external environment, which shortens the service life and seriously restricts the popularization and application of this kind of material. Aiming at this problem, the work aims to investigate the effect of shot peening on the surface integrity and corrosion resistance of 2A97 Al-Li alloy. The effect of shot peening on machined surface integrity of Al-Li alloy was studied by orthogonal test. The influence of shot peening parameters, such as peening angle, shot diameter, peening speed and coverage, on the surface roughness, work hardening and residual stress was found out by range analysis, and the microstructure change was analyzed. The surface morphology of 2A97 before and after shot peening was analyzed by super depth of field three-dimensional microscope, the surface element distribution was analyzed by scanning electron microscope, and the microstructure was characterized by optical microscope. The effect of shot peening on the corrosion resistance of the alloy was compared and evaluated by electrochemical workstation and contact angle measuring instrument. The results showed that shot peening could cause severe plastic deformation in the surface layer of the sample, which increased the surface roughness, and led to surface defects such as peeling and cracks. Compared with the milling surface, the mass fraction of oxygen on the shot peening surface was 21.17%, which was more likely to form an oxide film. Shot peening impact angle and coverage had greater influence on the machined surface roughness than shot velocity and shot size. When the impact angle of the projectile was 45°, the surface of the material was corrugated due to the ploughing force. At the same time, work hardening and large surface residual compressive stress were introduced to the surface, the degree of work hardening fluctuated between 133% and 241%, the maximum work hardening layer depth was up to 250 μm, and the maximum surface residual compressive stress was −415.54 MPa. Coverage had the greatest influence on surface microhardness and residual stress. Compared with the sample without shot peening, the surface microstructure of the sample after shot peening was obviously refined. The microstructure of the surface layer consisted of a severe plastic deformation layer near the peened surface and a grain refinement layer within 200 μm from the peened surface. In 3.5% NaCl solution, the shot peening sample had better corrosion resistance, and the number and size of corrosion pits on the surface were significantly reduced. When the shot peening impact angle was 60°, the shot size was 0.8 mm, the shot velocity was 60 m/s and the coverage was 200%, the optimal processing parameters of improving the surface corrosion resistance by shot peening were obtained. Under this test condition, the corrosion potential of the workpiece was −1.099 2 V, which was much higher than that of the milling surface. After shot peening, the contact angle of the alloy surface was greater than 90°, and the alloy surface showed hydrophobic characteristics. Compared with the milling surface, the shot peening surface of 2A97 Al-Li alloy has better corrosion resistance. |
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