Optimization of strength by microstructural refinement of MgY2Zn1 alloy during extrusion and ECAP processing

A MgY2Zn1 alloy composed of a Mg matrix and about 19% of LPSO phase has been prepared by casting and further processing at high temperature by extrusion and equal channel angular pressing (ECAP). After extrusion an elongated microstructure was obtained in the direction of extrusion where the LPSO phase appears partially broken and the Mg matrix is partially recrystallized to very fine grain size. ECAP processing carried out both in the as-cast and extruded alloy leads to further grain refinement by recrystallization and also to further comminution of the LPSO particles. The increase in strength of the alloy by the different processing routes has been analysed in terms of the contributions from the LPSO particles and the deformed and the recrystallized grains in the magnesium matrix.