Deformation behavior of Mg-Zn-Y alloys reinforced by icosahedral quasicrystalline particles

New Mg-rich Mg-Zn-Y alloys, reinforced by quasicrystalline particles, have been developed by thermomechanical processes. The deformation behavior of these alloys at room and elevated temperatures has been investigated. Yield strength of these alloys, which increases with an increase in the volume fraction of quasicrystalline particles, is relatively high due to their strengthening effect. The variation of the flow stress in the alloys is characterized by linking the microstructural evolution during deformation at high temperatures. The flow softening is related to dynamic recrystallization developed under the dislocation climb controlled creep; the flow hardening is related to grain growth that occurs under the grain boundary diffusion controlled creep. Quasicrystalline particles in the Mg-Zn-Y alloys resist coarsening due to their low interfacial energy, thereby forming of stable quasicrystalline particle/matrix interface and also prohibit against microstructural evolution of the alpha-Mg matrix during deformation at temperatures up to near the eutectic temperature. Stability of both quasicrystalline particles and matrix microstructure in the Mg-Zn-Y alloys provides large elongation to failure with no void formation at the quasicrystalline particle/matrix interface. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.