Enhanced strength-ductility synergy of homogeneous isomeric Al–Cu–Mg sheet prepared by powder metallurgy

In this study, a new type of homogeneous isomeric mixed-crystal billet were prepared by hot pressing sintering first and then the isomeric Al–Cu–Mg alloy sheets with a good balance of strength and ductility were successfully prepared by extruding. The microstructure shows that a typical ‘shell core’ structure in which coarse grains coated with fine grains is formed in the sheet, and the ratio of coarse grains to fine grains in the sheet can be precisely controlled by adjusting the particle size of the powder. And the formation and modification mechanism of the homogeneous isomeric are thoroughly discussed in the present study. The results show that the coordinated deformation of coarse grains and the generation of dynamic recrystallization behavior during extrusion deformation of mixed-crystal billet are the main reasons for the formation of the ‘shell core’ structure in the sheets. When the proportion of coarse grains reaches 50%, the isomeric structure can be better preserved in the alloy sheet and the comprehensive properties of the homogeneous isomeric are better than those of the traditional sintered and extruded alloy sheet. The above study provides a new reference idea for the preparation and application of high-performance Al–Cu–Mg alloy sheets.