The < c + a > slip - twinning competition in hexagonal close packed metals.

We study the competition between twinning and slip in hexagonal close packed metals. Under a set of reasonable simplifying assumptions, we perform an explicit homogenization to derive an expression relating the macroscopic flow stress to the flow stresses of the different deformation mechanisms. The resulting expression is surprisingly simple and is parameterized by a single dimensionless variable related to the rate of deformation. Utilizing this expression, we pose a simple model for inelastic deformation in hexagonal close packed metals and apply it to examine stress-strain data in beryllium. [ABSTRACT FROM AUTHOR]