【摘要】 进行了不同温度、频率和应力比条件下喷射成形GH738合金紧凑拉伸(CT)试样的疲劳裂纹扩展试验,分析了相应条件下的疲劳裂纹扩展速率及其对疲劳裂纹扩展行为的影响规律。结果表明:随着温度的升高,裂纹扩展速率略有加快;加载频率降低,疲劳裂纹扩展加速;裂纹扩展速率da/d N随应力比R的增大而增大。疲劳断口呈现多裂纹源特征,裂纹稳定扩展为疲劳条带机制。更多还原

【Abstract】 The fatigue crack growth tests of spray formed GH738 superalloy with compact tension(CT)specimens were carried out at different temperatures,loading frequency and R-ratios.The effects of temperatures,loading frequency and R-ratios on fatigue crack growth behaviors were investigated.The results show that the crack propagation rate increases with the increase of temperature;Fatigue crack propagation increases with the decrease of loading frequency;Fatigue crack growth rate da/dNis also found to increase with the larger R-ratios.The crack initiates multi-sites,and the fatigue fracture individually exhibits a series of fatigue striations mode in the crack steady growth region.更多还原