摘要
应用超声疲劳试验技术,对两种高强度钢在20kHz频率下105-1010循环周次的疲劳性能进行了测试分析。结果表明:应力比R=-1时,D38MSV5S钢与100C6钢在105-1010循环周次之间,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;R=0.1时,D38MSV5S钢在105-107循环周次之间会出现疲劳强度。与30Hz频率下常规疲劳试验数据比较发现,频率对100C6钢的疲劳性能影响不大;R=-1时,D38MSV5S钢20kHz频率下的S-N曲线略低于30Hz频率下的SN曲线,当R=0.1时,频率对D38MSV5S钢疲劳性能的影响更为明显。在超高周疲劳循环下,疲劳破坏主要起源于试样内部夹杂物。
Super high cycle fatigue behavior of 100C6 and D38MSV5S high strength steels, were investigated using ultrasonic fatigue testing equipment at a frequency of 20 kHz up to 1010 cycles. The S-N curve at room temperature with different stress ratios CR=-1 and R=0. 1) was determined The experimental results show that fatigue strength decreased with increasing number of cycles between 105 and 1010 cycles for R= - 1, there was no fatigue limit; however, fatigue limit of D38MSV5S was found between 106 and 107 cycles for R=0. 1. S-N curves show that the results for 20 kHz testing agreed quite well with those for conventional 30 Hz testing in the 105-107 cycle range for 100C6; frequency effects were found in the testing of D38MSV5S, specially, frequency effect was very obvious for the testing with R = 0. 1. SEM examination of fracture surfaces reveals that fatigue damage was governed by the formation of cracks, and subsurface crack initiation was dominant in the very long-life range.
出处
《机械工程材料》
CAS
CSCD
北大核心
2005年第5期12-15,共4页
Materials For Mechanical Engineering
基金
国家自然科学基金资助项目(59975075)
关键词
超高周疲劳
S-N曲线
高强度钢
裂纹源
super high cycle fatigue
S-N curve
high strength steel
subsurface crack initiation
