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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Grain boundary carbides as hydrogen diffusion barrier in a Fe-Ni alloy
T2 - A thermal desorption and modelling study
AU - Turk, A.
AU - Bombač, D.
AU - Jelita Rydel, J.
AU - Ziętara, M.
AU - Rivera-Díaz-del-Castillo, Pedro E. J.
AU - Galindo-Nava, E.I.
PY - 2018/12/15
Y1 - 2018/12/15
N2 - A significant decrease in hydrogen absorption in the presence of grain boundary carbides compared to the carbide-free microstructure in the Ni-based HR6W alloy was measured by thermal desorption analysis (TDA). This novel observation is at odds with numerous existing reports – precipitate-rich microstructures generally absorb more hydrogen due to trapping effects. This discrepancy can only be explained by grain boundary diffusion which is known to be fast in Ni-based alloys. It is proposed that grain boundary diffusion is hindered by carbides, resulting in decreased hydrogen absorption. Further experimental evidence corroborates the hypothesis. In addition, a diffusion model was developed to quantify the experimental results, incorporating trapping, grain boundary diffusion and temperature effects. It was successfully applied to the reported TDA data as well as additional diffusion data from the literature. A parametric analysis showed that hydrogen absorption scales strongly with grain size and grain boundary diffusivity while grain boundary segregation energy has a much lower impact. The results of the study point at grain boundary precipitation as a possible means of hydrogen embrittlement mitigation in Ni alloys and austenitic stainless steels. © 2018
AB - A significant decrease in hydrogen absorption in the presence of grain boundary carbides compared to the carbide-free microstructure in the Ni-based HR6W alloy was measured by thermal desorption analysis (TDA). This novel observation is at odds with numerous existing reports – precipitate-rich microstructures generally absorb more hydrogen due to trapping effects. This discrepancy can only be explained by grain boundary diffusion which is known to be fast in Ni-based alloys. It is proposed that grain boundary diffusion is hindered by carbides, resulting in decreased hydrogen absorption. Further experimental evidence corroborates the hypothesis. In addition, a diffusion model was developed to quantify the experimental results, incorporating trapping, grain boundary diffusion and temperature effects. It was successfully applied to the reported TDA data as well as additional diffusion data from the literature. A parametric analysis showed that hydrogen absorption scales strongly with grain size and grain boundary diffusivity while grain boundary segregation energy has a much lower impact. The results of the study point at grain boundary precipitation as a possible means of hydrogen embrittlement mitigation in Ni alloys and austenitic stainless steels. © 2018
KW - Carbides
KW - Grain boundary diffusion
KW - Hydrogen diffusion
KW - Thermal desorption analysis (TDA)
KW - Binary alloys
KW - Diffusion barriers
KW - Grain boundaries
KW - Microstructure
KW - Nickel alloys
KW - Precipitation (chemical)
KW - Thermal desorption
KW - Grain boundary carbides
KW - Grain boundary diffusivity
KW - Grain boundary precipitation
KW - Grain boundary segregation
KW - Grain-boundary diffusion
KW - Hydrogen diffusion barriers
KW - Thermal desorption analysis
KW - Iron alloys
U2 - 10.1016/j.matdes.2018.10.012
DO - 10.1016/j.matdes.2018.10.012
M3 - Journal article
VL - 160
SP - 985
EP - 998
JO - Materials and Design
JF - Materials and Design
SN - 0264-1275
ER -