Hydrogen induced hardening effects on alpha iron: a molecular dynamics study

  • Author / Creator
    Xie, Wenbo
  • Molecular dynamics simulations were performed to investigate hydrogen interaction with edge dislocations during deformation in α-Fe. In particular, uniaxial tensile tests at different hydrogen concentration were conducted in a single crystal iron with high density of edge dislocations introduced by plastic deformation. During system relaxation, hydrogen atoms have tendency to diffuse and stay around dislocation line - a well-known hydrogen trap-site in α-Fe. Our simulations show that the yield strength of the bcc iron is very sensitive to the presence of hydrogen within edge dislocations, i.e., it increases as hydrogen concentration increasing. After yielding, the hydrogen atom is de-associated with the moving dislocations, suggesting that the yield strength enhancement is due to the hydrogen pinning effect. This direct observation of hydrogen hardening effects confirms the model suggested by Matsui etc. Additional simulations also indicate hydrogen interaction with edge dislocations is sensitive to temperature as well as vacancies around dislocation cores.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Department of Chemical and Materials Engineering
  • Supervisor / co-supervisor and their department(s)
    • Chen, Weixing(Chemical & Materials Engineering)
    • Zhang, Hao (Chemical & Materials Engineering)
  • Examining committee members and their departments
    • Tang, Tian (Mechanical Engineering)