Applied stress anisotropy effect on melting of tungsten: molecular dynamics study

Dulat Akzhigitov, Tamerlan Srymbetov, Boris Golman, Christos Spitas, Zhandos N. Utegulov

Research output: Contribution to journalArticlepeer-review

Abstract

Atomic-level insight into pre- and post- melting phenomena under complex stresses spanning compression, tension, and shearing in refractory metals is critical. The exploration of high temperature and melting behavior in tungsten under magnitude- and orientation-dependent uniaxial and biaxial compression and tension, approaching pure shear stresses was thoroughly investigated by molecular dynamics using extended Finnis-Sinclair potential. Using equilibrium solid-liquid coexistence simulations, we demonstrated the enhancement (reduction) of the melting point temperature Tm taking place with the increase of applied compression (tension) stress magnitudes, reaching a minimum under pure shear stress. Explored heating and melting behaviors under various stress types, magnitudes, and orientations were well supported by the corresponding trends in radial distribution function g(r) and Lindemann index δ. The highest resistance to melting was found under uniaxial compression likely due to bonds stiffening. On the other hand, the highest compliance to melting was revealed under pure shear stress, triggered by the accelerated vibrational instability and destruction of the bcc crystalline order driven by simultaneous shear deformation and formation of fcc and hcp phases.

Original languageEnglish
Article number111139
JournalComputational Materials Science
Volume204
DOIs
Publication statusPublished - Mar 2022

Keywords

  • Lindemann index
  • Melting temperature
  • Molecular dynamics
  • RDF
  • Stress anisotropy
  • Tungsten

ASJC Scopus subject areas

  • Computer Science(all)
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Computational Mathematics

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