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应用基于压电超声疲劳试验技术开发的20kHz弯曲疲劳试验系统,完成了室温下TC17合金超高周疲劳试验.结果表明:在疲劳循环大于107周次时,试样仍会发生疲劳断裂,疲劳强度随循环次数的增加而下降,并不存在明显的疲劳极限.TC17合金的应力-寿命(S-N)曲线在107～109周次的范围内为连续下降型.光学显微镜发现,TC17合金的疲劳破坏主要起源于试样表面.当存在夹杂物时,疲劳裂纹从距离表面很近的夹杂物处萌生,能谱分析表明夹杂物的成分主要是铝的氧化物.
The ultrahigh cycle fatigue test of TC17 alloy at room temperature was completed by using 20kHz bending fatigue test system based on piezoelectric ultrasonic fatigue test technology.The results show that the fatigue fracture With the increase of the number of cycles, there is no obvious fatigue limit.The stress-life (SN) curve of TC17 alloy is continuously descending in the range of 107 to 109. Optical microscopy shows that the fatigue failure of TC17 alloy is mainly Originated from the surface of the specimen.When inclusions are present, fatigue cracks initiate from inclusions close to the surface, and energy spectrum analysis shows that the inclusions mainly consist of aluminum oxide.