Improvement of abrasion resistance in artificial seawater and corrosion resistance in NaCl solution of 7075 aluminum alloy processed by laser shock peening

• Published in: Optics and lasers in engineering Vol. 90; pp. 179 - 185
• Main Authors: Wang, Hao, Ning, Chengyi, Huang, Yihui, Cao, Zhenya, Chen, Xiaoxiao, Zhang, Wenwu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2017
• Subjects: Abrasion resistance; Electrochemical corrosion behavior; Laser shock peening; Microhardness; Microstructure; Laser shock peening; Abrasion resistance; Microstructure; Microhardness; Electrochemical corrosion behavior
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/j.optlaseng.2016.10.016

As 7075 aluminum alloy is widely used in a humid environment, in order to enhance its abrasion resistance and electrochemical corrosion resistance, the paper studied the effect of laser shock peening on abrasion resistance in artificial seawater and corrosion resistance in 3.5% NaCl solution of 7075 aluminum alloy. Result shows that when specimens were treated once and twice with 7.17GW/cm2 the abrasion loss would be reduced by 43.75% and 46.09% compare to untreated respectively, and the corrosion rate of 7075 aluminum alloy could be reduced as much as 50.32% by LSP treatment with 7.17GW/cm2. What’s more, the effects on the microhardness, microstructure and residual stress with different LSP impacts and power density were investigated to find out strengthening mechanism of laser shock peening, which were observed and measured by microhardness tester, optical microscope and X-ray diffraction (XRD) residual stress tester. In the entire laboratory tests, it is considered that LSP is a practical option to improve abrasion resistance in seawater and corrosion resistance of 7075 aluminum alloy.
•Experiments were carried out with a Nd:YAG laser system and the laser spot is elliptical spot.•The typical material of 7075 aluminum alloy was taken to investigate the effect of laser shock peening with different LSP parameters on abrasion resistance in seawater and electrochemical corrosion behavior in 3.5% NaCl solution.•It has been demonstrated that specimens were treated once and twice with 7.17GW/cm2 the abrasion loss would be reduced by 43.75% and 46.09% compare to untreated respectively, and the corrosion rate of 7075 aluminum alloy could be reduced as much as 50.32% by LSP treatment with 7.17GW/cm2.•When 7075 aluminum alloy is used in marine vessel or aircraft to make skeletons, rivet, aero-engine blades and propeller blade which often fly from offshore platform or airplane carrier, it will frequently be exposed to rain. Seawater and abrasion and corrosion may be caused by seawater and sea-salt spray. It was found that LSP is a practical option to enhance abrasion property in seawater and corrosion property. The results obtained in this paper could not only save lots of resource but also reduce maintenance cost, making the material longer life.