Emerging trends in plasticity and precipitation of Al-Li-X alloys

Abstract

Increasing interests of aerospace engineering for slender designs have accepted Al-Li-X alloys as a light weight, high modulus and superplastic alloy. The plasticity to superplasticity has defined from typical elongation data from 10's order to 100's order percentiles. The trends of development have elaborated to encourage dynamic recrystallization for grain refining during superplastic deformation. 8090 alloys have strategically described where arrests of fine precipitation to grain coarsening have included additive plasticity effects. Cavitations at precipitate interfaces or large angle grain boundaries have directed interests to model alloys from studies of intergranular orientation. Grain boundaries sliding have been primary mode in this respect, which has enhanced by intergranular rotation than misorientation. Studies of orientation imaging microscopy (OIM) have found to be successful for correct delineation. Equal channel angular extrusion have appeared to produce ultra fine submicron grained (SMG) microstructure free of precipitate free zones without requirement of preage stretch for aerospace cryogenic applications. In precipitation mechanism description have included evaluation and controversies among a, q', T1, TB, R and W-phases, and GP-I and II zones for d' phase formation respectively.