Fatigue strength and crack initiation mechanism of very-high-cycle fatigue for low alloy steels | |
Hong YS(洪友士)![]() ![]() ![]() | |
Source Publication | METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE |
2012-08 | |
Pages | 2753-2762 |
Conference Name | 8th Symposium on Bulk Metallic Glasses (BMGs)/TMC Annual Meeting and Exhibition |
Conference Date | FEB 27-MAR 03, 2011 |
Conference Place | San Diego, CA |
Abstract | The fatigue strength and crack initiation mechanisms of very-high-cycle fatigue (VHCF) for two low alloy steels were investigated. Rotary bending tests at 52.5 Hz with hour-glass type specimens were carried out to obtain the fatigue propensity of the test steels, for which the failure occurred up to the VHCF regime of 10(8) cycles with the S-N curves of stepwise tendency. Fractography observations show that the crack initiation of VHCF is at subsurface inclusion with "fish-eye" pattern. The fish-eye is of equiaxed shape and tends to tangent the specimen surface. The size of the fish-eye becomes large with the increasing depth of related inclusion from the surface. The fish-eye crack grows faster outward to the specimen surface than inward. The values of the stress intensity factor (K (I) ) at different regions of fracture surface were calculated, indicating that the K (I) value of fish-eye crack is close to the value of relevant fatigue threshold (Delta K (th) ). A new parameter was proposed to interpret the competition mechanism of fatigue crack initiation at the specimen surface or at the subsurface. The simulation results indicate that large inclusion size, small grain size, and high strength of material will promote fatigue crack initiation at the specimen subsurface, which are in agreement with experimental observations. |
Keyword | Chromium-bearing Steel Long-life Fatigue S-n Curve Metallic Materials Behavior Failure Regime Stress |
Department | 非线性力学国家重点实验室 |
URL | 查看原文 |
Indexed By | CPCI-S ; EI |
Language | 英语 |
Document Type | 会议论文 |
Identifier | http://dspace.imech.ac.cn/handle/311007/46827 |
Collection | 非线性力学国家重点实验室 |
Corresponding Author | Hong, YS (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China. |
Recommended Citation GB/T 7714 | Hong YS,Zhao AG,Qian GA,et al. Fatigue strength and crack initiation mechanism of very-high-cycle fatigue for low alloy steels[C]METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE,2012:2753-2762. |
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