Lu Jiang¹, Velimir Radmilović², Julian E.C. Sabisch³, Liang Qi⁴, Andrew M. Minor¹, Daryl Chrzan¹, Mark Asta¹; ¹University of California, Berkeley, ²University of Belgrade, ³Sandia National Laboratories, ⁴University of Michigan

Dislocation slip and twinning are two essential plastic deformation mechanisms in materials, which impact the mechanical properties. An anisotropic elasticity model is developed based on density functional theory calculated material parameters to understand the unique mechanical properties of rhenium relative to other HCP metals. Specifically, rhenium shows predominant twinning in the {11-21} system, and restricted dislocation slip. The mechanism of {11-21} twin nucleation from edge dislocation is predicted to be favored in rhenium regardless of the stress condition while limited or conditionally operative in other HCP metals. The model thus provides insights into the origins of the relatively unique deformation modes in rhenium, which are supported by high-resolution electron microscopy results. The elasticity model can be further used in alloy design for identifying possible replacements for rhenium in high-temperature structural applications. This research is supported by the Office of Naval Research under grant N00014-16-1-3124.