GH4169镍基高温合金的高温低周疲劳性能

摘要

对国产GH4169镍基高温合金进行了总应变控制的高温低周疲劳试验,研究了其疲劳性能,分析了断口形貌.结果表明:试验合金具有较好的高温低周疲劳性能,与进口Inconel 718镍基合金的相近,但在较低的总应变范围下比Inconel 718合金的疲劳寿命要低;该合金在不同总应变范围下都表现出明显的循环软化行为;合金试样的疲劳断口呈多裂纹源性,疲劳源数量随总应变范围的降低和疲劳寿命的延长而减少;疲劳裂纹都萌生于表面,穿晶扩展到一定径向深度时,会出现沿晶扩展特征.%The total strain controlled high-temperature low-cycle fatigue experiments were conducted on the domestic GH4169 Ni-based superalloy.The fatigue properties of the alloy were studied and the fracture morphology was analyzed.The results show that the tested alloy had a superior low-cycle fatigue performance at elevated temperature,which was similar to that of imported Inconel 718 Ni-based alloy,but lower than the fatigue life of the Inconel 718 alloy at a relatively low total strain range.The cyclic stress softening behavior of the alloy was presented at different total strain ranges.The fatigue fractures of the alloy specimens showed a character of multi-crack sources and the crack source amounts decreased with the decrease of the total strain range and the prolonging of the fatigue life.The fatigue cracks all initiated at the specimen surface,and when propagated in an intergranular mode to a certain radial depth,showed a transgranular propagation characteristic.