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利用超声疲劳试验设备在20kHz频率下研究了一种高强度钢的超高周疲劳性能,试验持续到109次循环,得到了室温环境及不同循环比(R=0.01和R=0.1)的S-N曲线,试验结果显示,疲劳强度在105～109次循环范围内随着循环次数的增加而减小。断面表面的SEM检查结果表明,疲劳裂纹的生成导致疲劳损伤,且亚表面裂纹起源在长寿命范围内。试验结果表明,试件全寿命的99.87%贡献于亚表面裂纹的形成。
The ultrahigh-cycle fatigue behavior of a high-strength steel was investigated using ultrasonic fatigue testing equipment at a frequency of 20 kHz. The test lasted until 109 cycles and the SN curve was obtained at room temperature with different cycle ratios (R = 0.01 and R = 0.1) The experimental results show that the fatigue strength decreases with the increase of the number of cycles in the range of 105 ~ 109 cycles. The results of SEM examination of the cross-section surface show that fatigue crack generation leads to fatigue damage, and the origin of sub-surface cracks is in the long-life range. The test results show that 99.87% of the whole life of the specimen contributes to the formation of sub-surface cracks.