直接时效GH4169合金疲劳断口分析研究  

Fracture Performance of Direct Aging GH4169 Superalloy

作　　者：谢孝昌[1] 柴志刚[2] 李权[2] 汤春峰[1] 赵振业[1] 

机构地区：[1]北京航空材料研究院,北京100095 [2]北京航空工程技术研究中心,北京100076

出　　处：《航空材料学报》2015年第5期46-56,共11页Journal of Aeronautical Materials

基　　金：973项目(61385)

摘　　要：采用扫描电镜对直接时效(DA)GH4169合金在室温和650℃下的光滑(Kt=1)和缺口(Kt=3、4)旋转弯曲疲劳试样断口进行了研究。研究表明,DAGH4169合金室温旋转弯曲疲劳光滑(Kt=1)试样断口在大应力状态下具有多源疲劳断裂特征,在低应力状态下则具有单源疲劳断裂特征,且疲劳裂纹均起始于表面加工缺陷处。DAGH4169合金室温旋转弯曲疲劳缺口(Kt=3,4)试样均起源于缺口根部的加工缺陷处,在实验载荷下均呈现多源疲劳断裂特征。DAGH4169合金650℃旋转弯曲疲劳光滑(Kt=1)试样断口呈单源疲劳断裂特征,起始于外表面加工缺陷处。DAGH4169合金650℃旋转弯曲疲劳缺口(Kt=3,4)试样均起源于缺口根部加工缺陷处,呈多源疲劳断裂特征。所有观察试样随疲劳载荷的逐渐降低,疲劳源区逐渐平滑,疲劳扩展逐渐充分,瞬断区面积逐渐减小,瞬断区的偏心距离逐渐增大。The fatigue fracture surface of DAGH4169 superalloy smooth specimen（ Kt= 1） and notch specimen（ Kt= 3,4） after rotating bending fatigue test carried out at room temperature and 650℃ were investigated by Scanning Electron Microscope（ SEM）. The results indicate that the fatigue fracture surface of DAGH4169 superalloy smooth specimen（ Kt= 1） at room temperature has multiple crack initiation feature under high fatigue load,while single crack initiation feature under low fatigue load. And the fatigue cracks initiate at the machining defects of the surface. Multiple cracks initiated at the machining defects of the notch foot under different level fatigue load is observed for the DAGH4169 superalloy notch specimen（ Kt= 3,4） at room temperature. Single crack initiated at machining defects of the surface is observed from the fatigue fracture surface of DAGH4169 superalloy smooth specimen（ Kt= 1） at 650℃.And DAGH4169 superalloy notch specimen（ Kt= 3,4） shows multiple crack initiation feature,the fatigue cracks initiate at the machining defects of the notch foot. For all the observed specimens,as fatigue load decreases,crack initiation region becomes smooth,the area of fatigue failure region becomes smaller,the distance between fatigue failure region and centre of fracture is bigger.

关 键 词：DAGH4169 疲劳断口 疲劳源 疲劳扩展 

分 类 号：TG146.15[一般工业技术—材料科学与工程]