Journal
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Volume 739, Issue -, Pages 404-414Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.msea.2018.10.073
Keywords
Very high cycle fatigue; Bainite; Retained austenite; Fracture mechanism; Non-inclusion induced crack initiation
Categories
Funding
- National Natural Science Foundation of China [51771014, U1760104]
- Fundamental Research Funds for the Central Universities [2017JBM053]
- Natural Science Foundation of Beijing [2172047]
- Central Iron & Steel Research Institute
Ask authors/readers for more resources
We studied the mutual and relative effect of inclusion and microstructure on very high cycle fatigue (VHCF) behavior of bainite/martensite (B/M) multiphase steel by designing four combinations of various inclusion sizes and microstructures. Results show that the fatigue crack initiations are mostly induced by inclusions in the specimens with large inclusion size, whereas the non-inclusion induced crack initiations (NIICI) are observed in the specimens whose microstructure is coarse. Unlike the inclusion induced cracks that grow along the plane of maximum tensile stress, the early non-inclusion induced cracks within micro-facet propagate along the plane of maximum shear stress (Le., Stage I crack), which is related to the strain localization in oriented B/M laths during cyclic loading. Finally, with the assistance of scanning electron microscopy, electron backscatter diffraction, 3-Dimensional surface profile, focused ion beam and transmission electron microscopy, we proposed the NIICI mechanism of coarse B/M microstructure, and found the orientation and size of coarse B/M block and blocky retained austenite (RA) are crucial microstructural factors in facilitating the formation of NIICI within VHCF regime.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available