激光冲击/喷丸复合强化对K4169铸造合金的表面完整性和疲劳性能的影响  

Effect of Combination of Laser Shock Peening and Shot Peening on Surface Integrity and Fatigue Property of K4169 Casting Alloy

作　　者：罗学昆 张文灿 吴波 田凯 王琨 王一鸣 王欣 LUO Xuekun;ZHANG Wencan;WU Bo;TIAN Kai;WANG Kun;WANG Yiming;WANG Xin(Aviation Key Laboratory of Advanced Corrosion and Protection on Aviation Materials,AECC Beijing Institute of Aeronautical Material,Beijing 100095,China;AECC Hunan Aviation Powerplant Research Institute,Zhuzhou 412002,China)

机构地区：[1]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 [2]中国航发湖南动力机械研究所,株洲412002

出　　处：《航空制造技术》2022年第11期57-62,共6页Aeronautical Manufacturing Technology

基　　金：国家重大科学与技术专项(J2017–VII–0001–0094,J2019–VII–0015–0155);中国航发创新平台项目(CXPT–2019–034,2021050386–JS)。

摘　　要：K4169合金广泛应用于制造航空发动机静子部件。针对K4169合金高温疲劳性能提升的需求,对旋转弯曲疲劳缺口试样进行了激光冲击/喷丸复合强化处理。对比分析了单一喷丸与复合强化高温疲劳性能,并采用扫描电镜、白光干涉仪、X射线应力测量仪及显微硬度计等仪器分析了试样的疲劳断口、表面三维形貌、粗糙度、表面残余应力和显微硬度梯度,探讨了K4169铸造合金表面强化机制。结果表明,在647℃、450MPa条件下,复合强化表现出比单一喷丸更优异的疲劳寿命提升效果。复合强化后,疲劳裂纹源的数量下降,主裂纹源的萌生位置从表层转移至次表层,疲劳裂纹扩展速率下降。另外,表面微观应力集中系数Kt显著降低,从2.39降低至1.46,表面残余压应力显著提升,从–258MPa提高至–1140MPa,表层形成了深度约0.20mm的硬化层。这些表面完整性参数的变化是疲劳性能提升的重要原因。K4169 alloy is widely used to fabricate the stator component of aeroengine.In order to improve the hightemperature fatigue property of K4169 alloy,notch specimens for rotating bending fatigue were treated by the combination processing of laser shock peening(LSP)and shot peening(SP).The fatigue lives of single SP and combination processing(LSP+SP)were compared and analyzed.The fatigue fracture,three-dimensional surface morphology,roughness,surface residual stress and microhardness distribution were characterized by scanning electron microscopy(SEM),white light interferometer,X–ray diffractometer and microhardness tester.The mechanism of the combination processing on the fatigue performance was also investigated.The results indicate that the LSP+SP treatment shows better improvement of fatigue life than that of SP under the 647℃,450MPa conditions.After LSP+SP,the number of fatigue crack source decreases,and the location of the main source transferred from the surface to the subsurface.Moreover,the fatigue crack growth rate also decreases.In addition,the micro-stress concentration factor Kt of the surface decreased from 2.39 to 1.46,and the surface residual compressive stress increased from–258MPa to–1140MPa.A work hardening layer with the depth of about 0.20mm was also generated.The improvement of fatigue life is considered to be mainly ascribed to the change of above surface integrity parameters.

关 键 词：激光冲击(LSP) 喷丸(SP) 疲劳性能 残余应力 硬度 

分 类 号：V263[航空宇航科学与技术—航空宇航制造工程] V252[一般工业技术—材料科学与工程]