Elastic-plastic deformation of molybdenum single crystals shocked to 12.5 GPa: Crystal anisotropy effects

Journal Article · Wed Feb 06 23:00:00 EST 2019 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.5048131· OSTI ID:1493763

Mandal, A. ^[1]; Gupta, Y. M. ^[2]

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1. Institute for Shock Physics, Washington State University, Pullman, Washington 99164, USA; School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, USA; Institute for Shock Physics
2. Institute for Shock Physics, Washington State University, Pullman, Washington 99164, USA; Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, USA

Here, to understand crystal anisotropy effects on shock-induced elastic-plastic deformation of molybdenum (Mo), results from high-purity single crystals shocked along [110] and [111] orientations to an elastic impact stress of 12.5 GPa were obtained and compared with the [100] results previously reported [A. Mandal and Y. M Gupta, J. Appl. Phys. 121, 045903 (2017)]. Measured wave profiles showed a time-dependent response, and strong anisotropy was observed in the elastic wave attenuation with the propagation distance, elastic limits, shock speeds, and overall structure of the wave profiles. Resolved shear stresses on {110} $$\langle$$111$$\rangle$$ and {112} $$\langle$$111$$\rangle$$ slip systems provided insight into the observed anisotropy in elastic wave attenuation and elastic limits and showed that shear stresses, and not longitudinal stresses, are a better measure of strength in shocked single crystals. Under shock compression, resolved shear stresses at elastic limits were comparable to the Peierls stress of screw dislocations in Mo. Elastic wave attenuation was rapid when shear stresses were larger than the Peierls stress. Large differences in the elastic limits under shock and quasi-static loading are likely a consequence of the large Peierls stress value for Mo. Numerically simulated wave profiles, obtained using the dislocation-based plasticity model described in the [100] work, showed good agreement with all measured wave profiles but could not differentiate between the {110} $$\langle$$111$$\rangle$$ and {112} $$\langle$$111$$\rangle$$ slip systems. Overall, experimental results and corresponding numerical simulations for the three crystal orientations have provided a comprehensive insight into shock-induced elastic-plastic deformation of Mo single crystals, including the development of a continuum material model.

• Research Organization: Washington State Univ., Pullman, WA (United States). Institute for Shock Physics
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Defense Programs (DP) (NA-10)
• Grant/Contract Number: NA0002007
• OSTI ID: 1493763
• Alternate ID(s): OSTI ID: 1495157
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 5 Vol. 125; ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English