激光冲击/机械喷丸复合强化对TC4钛合金外物损伤疲劳性能的影响  

Effect of co-strengthening of laser impact/mechanical shot peening on fatigue performance of TC4 titanium alloy damaged by foreign objects

作　　者：田凯 帅仕祥 罗学昆 王欣 马世成 许春玲 TIAN Kai;SHUAI Shixiang;LUO Xuekun;WANG Xin;MA Shicheng;XU Chunling(Surface Engineering Institution,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Aviation Key Laboratory of Advanced Corrosion and Protection on Aviation Materials,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;AVIC Chengdu Aircraft Industrial(Group)Co.,LTD.,Chengdu 610091,China)

机构地区：[1]中国航发北京航空材料研究院表面工程研究所,北京100095 [2]中国航发北京航空材料研究院航空材料先进腐蚀与防护航空重点实验室,北京100095 [3]航空工业成都飞机工业(集团)有限责任公司,成都610091

出　　处：《航空材料学报》2023年第4期94-101,共8页Journal of Aeronautical Materials

基　　金：国家重大科学与技术专项(2017-VII-0001-0094、2019-VII-0015);中国航发创新平台项目(CXPT-2019-034、2021050386-JS)。

摘　　要：针对航空发动机叶片前缘外物损伤(foregin object damage,FOD)后疲劳性能严重下降的问题,采用激光冲击/机械喷丸复合强化对TC4钛合金薄壁试样进行表面处理。采用X射线衍射测量复合强化前后试样表面残余应力梯度分布;通过硬度计预制不同形状的凹坑在试样表面引入FOD,利用电磁振动台测试处理前后TC4钛合金薄壁试样的高周一阶振动疲劳寿命;通过扫描电镜分析疲劳断口形貌;采用有限元动力学数值仿真模拟FOD前后试样表面残余应力分布演化规律,揭示了复合强化层对FOD缺口疲劳性能的影响机制。结果表明:相比未强化的FOD和无FOD试样,复合强化FOD试样的平均疲劳寿命分别提高了370%和60%;复合强化后试样表层形成的深层残余压应力场(厚度500μm)是提高FOD试样疲劳寿命的重要原因。Aiming at the problem that the fatigue performance of aeroengine blade leading edge was seriously degraded after foreign object damage(FOD),the surface of TC4 titanium alloy thin wall specimen was treated by laser shock/mechanical shot peening,and the residual stress gradient distribution on the specimen surface before and after the composite strengthening was measured by X-ray diffraction method;The high order vibration fatigue life of TC4 titanium alloy thin wall specimens before and after treatment was tested by electromagnetic vibration table,and FOD was introduced into the specimen surface by fabricating pits of different shapes with a hardness tester;The fatigue fracture surface was analyzed by SEM;The evolution of residual stress distribution on the specimen surface before and after FOD was simulated by finite element dynamic numerical simulation,and the mechanism of the influence of the composite strengthening layer on the notch fatigue performance of FOD was revealed.The results show that the average fatigue life of the composite strengthened FOD specimen is 370%and 60%higher than that of the non strengthened FOD specimen and the non strengthened FOD specimen,respectively.The deep residual compressive stress field(thickness 500μm)formed on the surface layer of the specimen after composite strengthening is an important reason for increasing the fatigue life of FOD specimen.

关 键 词：激光冲击强化 喷丸 外物损伤 疲劳 数值仿真 

分 类 号：TG407[金属学及工艺—焊接]