Effect of laser shock processing on fatigue life of fastener hole  

激光冲击强化对紧固孔疲劳寿命的影响(英文)

作　　者：张兴权[1] 陈六三[1] 余晓流[1] 左立生[1] 周煜[1] 

机构地区：[1]安徽工业大学机械工程学院,马鞍山243002

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第4期969-974,共6页中国有色金属学报（英文版）

基　　金：Project (51175002) supported by the National Natural Science Foundation of China;Project (090414156) supported by the Natural Science Foundation of Anhui Province,China

摘　　要：The fatigue properties of laser shock processing （LSP） on both side surfaces of fastener hole with diameter of 3 mm in the LY12CZ aluminum alloy specimens were investigated. The superficial residual stress was measured by X-ray diffraction method. Fatigue experiments of specimens with and without LSP were performed, and the microstructural features of fracture of specimens were characterized by scanning electron microscopy （SEM）. The results indicate that the compressive residual stress can be induced into the surface of specimen, and the fatigue life of the specimen with LSP is 3.5 times as long as that of specimen without LSP. The location of fatigue crack initiation is transferred from the top surface to the sub-surface after LSP, and the fatigue striation spacing of the treated specimen during the expanding fatigue crack is narrower than that of the untreated specimen. Furthermore, the diameters of the dimples on the fatigue crack rupture zone of the specimen with LSP are relatively bigger, which is related to the serious plastic deformation in the material with LSP.研究激光冲击对航空铝合金LY12CZ紧固孔疲劳特性的影响,孔的直径为d3 mm。利用X射线衍射法测量残余应力,对试件进行疲劳断裂实验,并用扫描电子显微镜(SEM)观察试件疲劳断口的微观特征。结果表明:激光冲击会在紧固孔端面形成残余压应力,冲击试件的疲劳寿命是未冲击的3.5倍。通过断口的观察和比较发现,冲击后试件的疲劳裂纹源于次表层,而不是源于试件表层,冲击后疲劳断口快速扩展区的疲劳条纹间距比未冲击试件疲劳断口快速扩展区的疲劳条纹间距要小。另外,在冲击试件断裂区的韧窝明显比未冲击的要大,这与冲击时材料内发生塑性变形有关。

关 键 词：laser shock processing fastener hole fatigue life LY12CZ 

分 类 号：TG665[金属学及工艺—金属切削加工及机床]