Microstructure evolution and texture development in thermomechanically processed Mg–Li–Al based alloys

Abstract

Abstract In the present study, the influence of alloying and thermomechanical processing on the microstructure and texture evolution on the two Mg–Li–Al based alloys, namely Mg–9 wt% Li–7 wt% Al–1 wt% Sn (LAT971) and Mg–9 wt% Li–5 wt% Al–3 wt% Sn–1 wt% Zn (LATZ9531) has been elicited. Novel Mg–Li–Al based alloys were cast (induction melting under protective atmosphere) followed by hot rolling at ∼573 K with a cumulative reduction of five. A contrary dual phase dendritic microstructure rich in α-Mg, instead of β-Li phase predicted by equilibrium phase diagram of Mg–Li binary alloy was observed. Preferential presence of Mg–Li–Sn primary precipitates (size 4–10 μm) within α-Mg phase and Mg–Li–Al secondary precipitates ( ( 1 0 1 ¯ 0 ) slip planes. The quantification of the grain average misorientation (less than 2°) using electron backscattered diffraction confirmed the presence of strain free grains in majority of the grains (fraction >0.75) after hot-rolling of Mg–Li–Al based alloys. Role of alloying in rendering distribution of dual-phase structure has strongly influenced dynamic-recrystallization and grain-growth in the hot-rolled Mg–Li–Al based alloys.