Materials Research Letters (Mar 2024)

Non-Schmid effects in a model refractory multi-principal element alloy: phase-field dislocation dynamics informed by atomistic simulations

  • Hyojung Kim,
  • Nithin Mathew,
  • Darby J. Luscher,
  • Abigail Hunter

DOI
https://doi.org/10.1080/21663831.2024.2313104
Journal volume & issue
Vol. 12, no. 3
pp. 190 – 198

Abstract

Read online

Non-Schmid effects in a representative refractory multi-principal element alloy (MPEA), MoNbTi, are investigated using molecular statics (MS) and phase field dislocation dynamics (PFDD). In addition to imposing a statistical distribution for the energetic barrier to slip, incorporating properties of the screw dislocation core is critical in capturing the wide range of MS-predicted non-Schmid effects. PFDD energy terms are enhanced to better capture the varying screw dislocation core-widths under loading as informed by MS. These enhancements demonstrate that incorporating the details of screw dislocation cores, in different chemical environments, has the strongest effect on representing the MS-predicted range of non-Schmid effects.Impact StatementVarying degrees of non-Schmid effects, unique to refractory MPEAs, are studied for the first time using atomistic and mesoscale models and are shown to result from environment-dependent properties of screw dislocation cores.

Keywords