Microstructure and Texture Changes of MgLiAl Alloys Composed of α or α + β Phases after Twist Channel Angular Pressing TCAP

Two MgLiAl alloys of composition 4.5% Li and 1.5% Al (in wt.%) composed of α phase and of 9% Li, 1.5% Al composed of α (hcp) + β (bcc) phases were subjected to twist channel angular pressing (TCAP) deformation. Such deformation of α + β alloys caused less effective grain refinement than that of single α phase alloy. However, with increasing number of passes, grain size of single α phase alloy increased and that of β phase in two phase α + β alloy also grew, which suggested the effect of dynamic recrystallization. TEM studies allowed identifying particles of Li₂MgAl phase of size of few μm. {001}<100> texture was observed in extruded alloy. Texture studies of extruded and TCAPed single phase hcp alloy indicated texture with {1010} plane perpendicular to the extrusion direction and {0002} plane parallel to the extrusion direction. Duplex α + β alloys showed poor texture development.