Surface Crack Initiation Phenomenon in Very High Cycle Fatigue
Very High Cycle Fatigue behavior of Stainless Steel AISI 310 has been investigated through ultrasonic fatigue testing.In fatigue cycles,a horizontal asymptote of S-N curve was found without any step at 106 cycles.Surface crack initiation was found irrespective of the stress level.However,the fracture surfaces of the material showed different behavior of crack propagation for different stages of fatigue cycles.It was found that up to 106 cycles,cracks initiated from surface defects and carbide precipitates present on the grain boundaries.The mechanism of crack initiation changed at low stress levels and slip bands and deformation twins were found at the surface of the specimen which acted as fatigue crack initiation sites.At lower stress levels,at or below fatigue limit,PSBs were developed but the cracks were not initiated.The lower slope in S-N curve was attributed to the development of PSBs all over the surface of the specimen before crack initiation.
Very high cycle fatigue Crack initiation PSBs Local plasticity
MuhammadKashif Khan QingYuan Wang
Department of Mechanics and Engineering Science,Sichuan University,Chengdu 610065,China
国际会议
北京
英文
1-10
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）