连续激光冲击强化7050铝合金中厚板的过喷效应  

Over Peening Effect of Al7050 Mid-thick Plates with Continued Multiple Laser Shock Peening Impacts at the Same Position

作　　者：吴俊峰 邹世坤 巩水利 曹子文 车志刚 孙汝剑 Wu Junfeng;Zou Shikun;Gong Shuili;Cao Ziwen;Che Zhigang;Sun Rujian(Science and Technology on Power Beam Processes Laboratory,AVIC Manufacturing Technology Institute,Beijing 100024,China)

机构地区：[1]中国航空制造技术研究院高能束流加工技术国家级重点实验室,北京100024

出　　处：《稀有金属材料与工程》2020年第10期3395-3401,共7页Rare Metal Materials and Engineering

基　　金：National Science and Technology Major Project of China(2016YFB1102700);National Natural Science Foundation of China(51875542);Civil Aircraft Research Project(MJ-2016-F-16);Aviation Fund(20185425009)。

摘　　要：基于连续激光冲击强化7050铝合金中厚板的表面完整性和内部层裂,提出了一种激光冲击强化的过喷效应。7050铝合金中厚板尺寸为50 mm×50 mm×5 mm(长×宽×高)。激光工艺参数为激光能量30 J,光斑尺寸4 mm×4 mm,脉宽15 ns和单点连续多次激光冲击(LSP-1~LSP-8)。表面形貌,表面残余应力,深度方向显微硬度和截面微观组织分别用超景深三维形貌仪,X射线衍射仪,显微硬度仪和金相显微镜测试分析。研究结果表明:单点连续5次激光冲击诱导7050铝合金中厚板表面微凹坑凸起高度为197.8μm和山脊高度为130.8μm。从单点连续4次激光冲击到单点连续5次激光冲击,试样表面残余应力由压应力转换为拉应力。单点连续5次激光冲击后,试样背层产生了低显微硬度的加工软化现象。单点连续5次激光冲击为7050铝合金中厚板的层裂阈值。研究结果有益于激光冲击强化工业应用中避免层裂和改善强化效果。An over peening effect was presented based on the researches of surface integrity and internal spall of Al7050 mid-thick plates with continued multiple laser shock peening(LSP)impacts at the same position.The dimensions of the samples were 50 mm×50 mm×5 mm(length×width×thickness).Laser process parameters were laser energy of 30 J,square spots of 4 mm×4 mm,pulse width of 15 ns and continued multiple LSP impacts at the same position(LSP-1~LSP-8).Surface morphology,surface residual stress,and micro-hardness in depth and cross-sectional microstructure were measured by super depth 3D microscope system,X-ray diffraction instrument,Vickers indenter and optical microscope(OM),respectively.The results indicate that high micro-dent depressions of 197.8μm and ridges of 130.8μm are generated after continued LSP-5.Surface compressive residual stress changes into tensile residual stress from continued LSP-4 to continued LSP-5.After continued LSP-5,work softing with low micro-hardness is found in the bottom layer.Continued LSP-5 is the spall threshold of Al7050 mid-thick plates.The research is beneficial to avoid the spall and improve the strengthening effect in the industry application of LSP.

关 键 词：7050铝合金中厚板 激光冲击强化 过喷效应 表面完整性 内部层裂 

分 类 号：TG665[金属学及工艺—金属切削加工及机床] TG146.21[一般工业技术—材料科学与工程]