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Atomistic investigation of hydrogen induced decohesion of Ni grain boundaries

Journal Article


Abstract


  • The embrittlement of metallic materials by hydrogen (H) segregation is widely observed, but not understood well on an atomic scale. In the present study, an atomistic investigation of H embrittlement of various grain boundaries (GBs) has been performed by mapping H segregation energy of trapping sites and examining the effect of H segregation on the decohesion of GBs. The simulation results show that under the equilibrium concentration of H atoms typical of embrittlement in Ni, in conjunction with local H diffusion process, the maximum reduction of tensile strength and fracture energy is 6.60% and 15.75% for Σ5 (210) ⟨100⟩ and Σ17 (530) ⟨100⟩ GBs, respectively. Inspired by experimental observations of the dislocation structures beneath intergranular failure features, further calculations reveal that the embrittling effect of H atoms in metallic materials can be largely facilitated by the boundary disruption and local stress state concentrated on the GB through the plasticity process. The findings directly provide a picture of H embrittlement arising from the cooperative action of H-induced plasticity and GB decohesion.

UOW Authors


  •   Li, Jiaqing (external author)
  •   Zhang, Che (external author)
  •   Wang, Rui (external author)
  •   Wang, Rui (external author)
  •   Lu, Cheng

Publication Date


  • 2020

Citation


  • Li, J., Lu, C., Pei, L., Zhang, C., & Wang, R. (2020). Atomistic investigation of hydrogen induced decohesion of Ni grain boundaries. Mechanics of Materials, 150. doi:10.1016/j.mechmat.2020.103586

Scopus Eid


  • 2-s2.0-85091246108

Volume


  • 150

Abstract


  • The embrittlement of metallic materials by hydrogen (H) segregation is widely observed, but not understood well on an atomic scale. In the present study, an atomistic investigation of H embrittlement of various grain boundaries (GBs) has been performed by mapping H segregation energy of trapping sites and examining the effect of H segregation on the decohesion of GBs. The simulation results show that under the equilibrium concentration of H atoms typical of embrittlement in Ni, in conjunction with local H diffusion process, the maximum reduction of tensile strength and fracture energy is 6.60% and 15.75% for Σ5 (210) ⟨100⟩ and Σ17 (530) ⟨100⟩ GBs, respectively. Inspired by experimental observations of the dislocation structures beneath intergranular failure features, further calculations reveal that the embrittling effect of H atoms in metallic materials can be largely facilitated by the boundary disruption and local stress state concentrated on the GB through the plasticity process. The findings directly provide a picture of H embrittlement arising from the cooperative action of H-induced plasticity and GB decohesion.

UOW Authors


  •   Li, Jiaqing (external author)
  •   Zhang, Che (external author)
  •   Wang, Rui (external author)
  •   Wang, Rui (external author)
  •   Lu, Cheng

Publication Date


  • 2020

Citation


  • Li, J., Lu, C., Pei, L., Zhang, C., & Wang, R. (2020). Atomistic investigation of hydrogen induced decohesion of Ni grain boundaries. Mechanics of Materials, 150. doi:10.1016/j.mechmat.2020.103586

Scopus Eid


  • 2-s2.0-85091246108

Volume


  • 150