Temperature and composition dependent screw dislocation mobility in austenitic stainless steels from large-scale molecular dynamics

Kevin Chu, Michael E. Foster, Ryan B. Sills, Xiaowang Zhou, Ting Zhu, David L. McDowell

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Extensive molecular dynamics simulations are performed to determine screw dislocation mobility in austenitic Fe0.7NixCr0.3-x stainless steels as a function of temperature ranging from 100 to 1300 K, resolved shear stress from 30 to 140 MPa, and Ni composition from 0.0 to 30.0 at%. These mobility data are fitted to a linear mobility law with a nonzero stress offset, referred to as the threshold stress. We find that both the linear drag coefficient and the threshold stress increase with Ni composition. The drag coefficient increases with temperature, whereas the threshold stress decreases with temperature. Based on these calculations, we determine fitting functions for the linear solute drag coefficient as a function of temperature and composition. The mobility laws determined in this study may serve to inform dislocation dynamics simulations pertinent to dislocation network evolution at elevated temperatures for a wide composition range of austenitic stainless steels.

Original languageEnglish (US)
Article number179
Journalnpj Computational Materials
Volume6
Issue number1
DOIs
StatePublished - Dec 2020

All Science Journal Classification (ASJC) codes

  • Modeling and Simulation
  • Materials Science(all)
  • Mechanics of Materials
  • Computer Science Applications

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