Microstructure and texture changes of MgLiAl alloys composed of alpha or alpha plus beta phases after twist channel angular pressing tcap

Abstract

Two MgLiAl alloys of composition 4.5% Li and 1.5% Al (in wt.%) composed of alpha phase and of 9% Li, 1.5% Al composed of alpha(hcp) + beta(bcc) phases were subjected to twist channel angular pressing (TCAP) deformation. Such deformation of alpha + beta alloys caused less effective grain refinement than that of single alpha phase alloy. However, with increasing number of passes, grain size of single alpha phase alloy increased and that of beta phase in two phase alpha + beta alloy also grew, which suggested the effect of dynamic recrystallization. TEM studies allowed identifying particles of Li2MgAl phase of size of few mu m. {001}<100> texture was observed in extruded alloy. Texture studies of extruded and TCAPed single phase hcp alloy indicated texture with {10 (1) over bar0} plane perpendicular to the extrusion direction and {0002} plane parallel to the extrusion direction. Duplex alpha + beta alloys showed poor texture development.