激光冲击对冷喷涂纯铝涂层表面形貌的影响  

Effect of Laser Shock Peening on Surface Morphology of Cold-Sprayed Pure Aluminum Coating

作　　者：赵恺 陈凯 姜高强 王星宇 孙潘杰 崔承云[1] Zhao Kai;Chen Kai;Jiang Gaoqiang;Wang Xingyu;Sun Panjie;Cui Chengyun(School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China)

机构地区：[1]江苏大学机械工程学院,江苏镇江212013

出　　处：《中国激光》2023年第4期34-42,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(51875267,51505198);江苏高校“青蓝工程”项目;江苏大学青年骨干教师计划;江苏大学大学生科研立项资助项目(20AA0092);江苏大学工业中心大学生创新实践基金(ZXJG202103)。

摘　　要：为了改善冷喷涂纯铝涂层表面形貌,结合激光冲击强化技术与冷喷涂技术,使用低压冷喷涂设备,以压缩空气作为介质,在镁合金表面上制备了一层纯铝涂层,研究了冷喷涂纯铝涂层在不同激光冲击次数作用下的表面形貌、粗糙度、物相、残余应力和显微硬度的变化。试验结果表明,激光冲击后涂层表面形貌趋于平整,激光冲击1、2、3次后的表面粗糙度相较于原始涂层分别降低了30.67%、50.96%、58.53%,但粗糙度降幅逐渐下降,残余应力状态由拉应力逐渐转变为压应力,涂层表面显微硬度分别提高了16.22%、27.46%、34.49%,单次的增幅呈现下降趋势。首次激光冲击对涂层表面的作用效果最为明显,后续冲击的作用效果不断衰减,总体作用效果随激光冲击次数的增加而不断提升。Objective Facing the long-term problem of poor corrosion resistance of magnesium alloys,it is considered that preparing coatings on the surface of magnesium alloy substrates is an effective means.Dense coatings can effectively isolate Mg alloys from external corrosive environments.Compared with coating preparation techniques,such as thermal spraying,which requires molten material,cold spraying avoids the melting and recrystallization of materials,high-temperature oxidation,stress cracking,and other problems.However,the surface of the coating generally has high roughness,which has an adverse effect on the anti-corrosion performance.Laser shock peening can effectively improve the surface morphology of the cold-sprayed coating and reduce the roughness of the coating surface.Simultaneously,problems,such as oxidation and material cracking,caused by thermal effect are avoided,maintaining the advantages of cold spraying.In addition,laser shock peening can improve the residual stress state of the coating surface and increase its microhardness.Methods In this paper,the mechanism of the effect of multiple laser shock peenings(LSPs)on the surface morphology of coldsprayed pure aluminum coatings is discussed.A pure aluminum coating is prepared on the surface of a magnesium alloy by cold spraying.A nanosecond-laser transmitter is used to shock the surface of the cold-sprayed coating.The laser pulse energy is 4 J,spot diameter is 3 mm,and overlap rate is 50%.The effect of LSPs with different impact numbers on the surface morphology,roughness value,phasu,residual stress state,and microhardness of the coatings are studied.The surface morphologies of the coatings before and after laser shock are measured using a confocal laser microscopy.The 3D and 2D profiles are used to describe the change in the coating surface morphology before and after laser shock,and the evolution process and mechanism of the coating surface morphology during laser shock are analyzed.The phase composition of the coating before and after laser shock is dete

关 键 词：激光技术 激光冲击强化 冷喷涂 纯铝涂层 粗糙度 塑性变形 

分 类 号：TN249[电子电信—物理电子学]