Title: Shock compression/release of magnesium single crystals along a low-symmetry orientation: Role of basal slip

Abstract

To gain insight into the relative contributions of different plastic deformation mechanisms, particularly basal slip, for shocked hexagonal close-packed (hcp) metals, magnesium (Mg) single crystals were subjected to shock compression and release along a low-symmetry (LS) orientation to 1.9 and 4.8 GPa elastic impact stresses. LS-axis is a “non-specific” direction resulting in propagation of quasi-longitudinal and quasi-shear waves. Wave profiles, measured using laser interferometry, show a small elastic wave followed by two plastic waves in compression; release wave profiles exhibited a structured response for the higher stress and a smooth response for the lower stress. The LS-axis wave profiles are significantly different than profiles published previously for c- and a-axes, demonstrating that Mg single crystals exhibit strong anisotropy under shock compression/release. Numerical simulations, using a time-dependent anisotropic modeling framework, show that shock wave loading along the LS-axis involves simultaneous operation of multiple deformation mechanisms. Shock compression along LS-axis is dominated by basal slip while prismatic and pyramidal I {$$10\bar{1}1$$} $$\langle$$ $$11\bar{2}3$$ $$\rangle$$ slip play a smaller role; coupling between longitudinal and shear deformations was observed. The unloading response is dominated by basal slip with some contribution from prismatic slip; pyramidal I slip is not activated. The present results, unlike results obtained for c- and a-axes, show that the deformation mechanism observed under quasi-static loading conditions along LS-axis is not sufficient to determine shock response along this orientation. Finally, although requiring numerical simulations for wave analysis, shock propagation along a LS orientation provides new insights into the plastic deformation response of hcp metal single crystals.

Authors:

Renganathan, P.  ^[1];

• Search DOE PAGES for author "Renganathan, P."
• Search DOE PAGES for ORCID "0000-0001-5012-806X"

Gupta, Y. M.  ^[2]

• Search DOE PAGES for author "Gupta, Y. M."
• Search DOE PAGES for ORCID "0000-0002-2669-3015"

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+ Show Author Affiliations

1. Washington State Univ., Pullman, WA (United States). Inst. for Shock Physics
2. Washington State Univ., Pullman, WA (United States). Inst. for Shock Physics; Washington State Univ., Pullman, WA (United States). Dept. of Physics and Astronomy

Publication Date:

Mon Sep 16 00:00:00 EDT 2019

Research Org.:

Washington State Univ., Pullman, WA (United States). Inst. for Shock Physics

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA), Office of Defense Programs (DP)

OSTI Identifier:

1574246

Alternate Identifier(s):

OSTI ID: 1562175

Grant/Contract Number:  

NA0002007

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Applied Physics

Additional Journal Information:

Journal Volume: 126; Journal Issue: 11; Journal ID: ISSN 0021-8979

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS