Effect of temperature, pressure, crystal defect types, and densities on the mechanical behavior of tungsten under tensile deformation: A molecular dynamics simulation study

A Alivaliollahi and G Alahyarizadeh and A Minuchehr, NUCLEAR MATERIALS AND ENERGY, 37, 101555 (2023).

DOI: 10.1016/j.nme.2023.101555

The mechanical behavior of tungsten under tensile deformation was investigated using molecular dynamics simulations, with a focus on the effects of temperature, pressure, crystal defect types, and densities. Single vacancies, spherical voids, and self-interstitials were studied at concentrations ranging from 0.1% to 2%. The Common neighbor analysis reveals that the crystal structure underwent a phase transition from the bodycentered cubic to the face-centered cubic structure at increasing levels of applied strain, followed by the formation of a disordered phase. Increasing temperature reduced the mechanical properties of tungsten, including yield strength, yield strain, modulus of elasticity, and ultimate tensile stress, possibly due to the activation of dislocation nucleation and propagation, resulting in the formation of dislocation loops. Increasing pressure enhanced the mechanical properties of tungsten, with the formation of dislocation loops occurring at much lower strains at higher pressures. All mechanical parameters decreased with increasing defect density, with selfinterstitial defects having a more severe effect than single vacancies and spherical voids. The number and length of dislocation loops also increased with increasing defect density. Temperature and pressure had varying effects on the stress-strain curve of tungsten with different defect types and densities, with increasing pressure generally enhancing its mechanical behavior and increasing temperature decreasing it. These findings provide valuable insights into the design and development of tungsten-based materials with enhanced mechanical properties.

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