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Your search keyword '"Fan, Y.H."' showing total 2 results
Start Over Author "Fan, Y.H." Topic embrittlement
2 results on '"Fan, Y.H."'

1. The role of delta ferrite in hydrogen embrittlement fracture of 17-4 PH stainless steel.

Author

Fan, Y.H., Zhao, H.L., Weng, K.R., Ma, C., Yang, H.X., Dong, X.L., Guo, C.W., and Li, Y.G.

Subjects
*HYDROGEN embrittlement of metals, *EMBRITTLEMENT, *KELVIN probe force microscopy, *STAINLESS steel, *HIGH strength steel, *FERRITES
Abstract

The role of δ-Fe in hydrogen embrittlement (HE) of 17-4 PH steel is studied in this work. Scanning Kelvin probe force microscopy result indicates that δ-Fe is a hydrogen trapping site. Accordingly, δ-Fe can reduce the hydrogen concentration of surrounding martensite and prior austenite grain boundaries (PAGBs) and imped the brittle fracture along lath boundaries and PAGBs, which can be beneficial to the HE resistance improvement. However, a cleavage fracture of δ-Fe can occur under the synergetic action of hydrogen-enhanced localized plasticity (HELP) and hydrogen enhancement of the strain-induced generation of vacancies (HESIV). These findings indicate a new path to improving HE resistance of high strength martensitic steels. • SKPFM result shows that hydrogen tends to segregate in delta ferrite. • Delta ferrite acting as a hydrogen trapping site decreases the tendency of brittle fracture. • Hydrogen segregation in delta ferrite leads to a strain localization and a subsequent transgranular cleavage fracture. [ABSTRACT FROM AUTHOR]

Published
2022
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2. Effect of grain refinement on the hydrogen embrittlement of 304 austenitic stainless steel.

Author

Fan, Y.H., Zhang, B., Wang, J.Q., Han, E.-H., and Ke, W.

Subjects
AUSTENITIC stainless steel, GRAIN refinement, HYDROGEN embrittlement of metals, EMBRITTLEMENT, CRYSTAL grain boundaries, GRAIN size
Abstract

The effect of grain size (in the range from 4 μm to 12 μm) on the hydrogen embrittlement (HE) of 304 austenitic stainless steel (ASS) was studied. HE susceptibility result shows that HE resistance increases with grain refinement. Electron backscattered diffraction kernel average misorientation (EBSD-KAM) mapping shows that the strain localization can be mitigated by grain refinement. Hence, strain localization sites which act as highways for hydrogen diffusion and preferred crack initiation sites can be reduced along with grain refinement, leading to a high HE resistance. Meanwhile, grain size shows no influence on the strain induced martensite (SIM) transformation during the hydrogen charging slow strain tensile test (SSRT). Hence, the SIM formed during hydrogen charging SSRT is not responsible for the different HE resistance of 304 ASSs with various grain sizes. Hydrogen diffusion is supposed to be controlled by a competition between short-circuit diffusion along random grain boundary (RGB) and hydrogen trapping at dislocations, leading to a maximum hydrogen diffusion coefficient in the 304 ASS with an average grain size of 8 μm. [ABSTRACT FROM AUTHOR]

Published
2019
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