Alloying effect of silver in magnesium on the development of microstructure and mechanical properties by indirect extrusion

Abstract

The effect of Ag in solid solution on the microstructure, texture and the deformation behaviour of indirectly extruded Mg was investigated. Ag as a solid solution strengthener affects the behaviour during extrusion, resulting in enhanced deformation related heating and corresponding coarser grained microstructures. No substantial effect on the texture development is revealed. The mechanical properties simultaneously increase in stress and strain levels with increasing Ag content, especially in tension as a result of the changing impact of the slip modes which can be associated with a decrease of the lattice parameters as well as the c/a ratio of the hcp lattice structure. In compression tests with twin dominated flow, the impact is much smaller on the compressive yield stress but higher with respect to the twinning related strain hardening rate. Solid solution strength functions for Fleischer and Labusch were determined, also confirming the anisotropic behaviour of the extruded Mg alloys.