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分别对DD432单晶高温合金的疲劳试验样品在750、850℃下对其进行疲劳性能测试。通过采用完全最大主应力的应力组合方式,针对平滑扭转试样进行高周疲劳试验。根据平滑试样试验数据和结果,采用Designlife数值模拟试验,分析了带凹口试样的扭转疲劳特点,并得出了相应的疲劳寿命关系。结果表明:在载荷谱一致的情况下,750℃时,平滑试样的寿命是带凹口试样的63142.5倍,而在850℃时,则降为3823倍。因此,表面缺陷是降低高温合金使用寿命的主因,其次则是环境温度。
The fatigue test of DD432 single crystal superalloy was carried out at 750 and 850 ℃ respectively. Through the use of the maximum total stress of the combination of stress for smooth torsional specimens for high-cycle fatigue test. According to the test data and the result of the smooth specimen, the Designlife numerical simulation test is used to analyze the torsional fatigue characteristics of the notched specimen and the corresponding fatigue life is obtained. The results show that at 750 ℃, the life of the smooth sample is 63142.5 times that of the notched sample and 3823 times at 850 ℃ when the load spectrum is consistent. Therefore, the surface defects are the main reasons to reduce the service life of superalloy, followed by the ambient temperature.