Anisotropic orientation dependent shock wave responses of monocrystalline molybdenum

Abstract

Molybdenum (Mo) demonstrates excellent industrial application potentials in micro-nano devices, which are inevitably subjected to shock loads during their application under harsh service environments. This study employs molecular dynamics (MD) simulations to investigate the shock responses of Mo under high-strain loading conditions with respect to the effects of crystal orientations. The findings reveal that monocrystalline Mo, along the shock direction of [111], exhibits inhomogeneous microstructure features characterized by significantly high-density and high-temperature localized regions. Once the rarefaction wave is produced, the physical parameters, including density and lateral pressure, will gradually decrease while normal pressure retains a residual value. The us-up, Pzz-up, and Pzz-V/V0 relations along the shock loading direction of [111] show deviations from those of [001] and [110] directions, with this difference being more pronounced for Pzz-V/V0. The formation of dislocations and the magnitude of shear stress experienced within the post-shock region are strongly dependent on crystal orientations. Specifically, an elevated probability of dislocation formation was observed along the [110] direction. Moreover, the magnitude of shear stress induced by shock loading along the [001] and [110] directions can exceed that of the [111] direction when the shock velocity is 1.5 km/s. The MD simulation results can serve as a valuable supplement to the investigations of mechanical properties pertaining to Mo.

Keywords

• Shock loading
• Orientation dependence
• Molybdenum
• Molecular dynamics
• Ultra-high strain rate