Severe plastic deformation close to the melting point enables Mg-Fe nanocomposites with exceptional strength

The attractive properties of Mg-bcc nanocomposites have gained increasing interest, but fabrication to bulk scales failed so far as strain immediately localizes within the Mg-phase. Targeting successful processing strate-gies, we analyze the deformation behavior and resulting microstructures of Mg-Fe composites as a function of applied strain and processing temperature using high-pressure torsion. Counterintuitively, processing at 73% of Mg's melting point accelerated microstructural refinement and improved homogeneity. Suppressing strain localization of the phases, a three-fold hardness increase compared to ambient processing is obtained. Such hardness levels suggest that further optimization likely paves the way towards bulk Mg-based materials beyond a gigapascal strength.

Automated summary

The attractive properties of Mg-bcc nanocomposites have gained increasing interest, but bulk fabrication has been unsuccessful due to strain localization within the Mg-phase. Through high-pressure torsion, the deformation behavior and resulting microstructures of Mg-Fe composites were analyzed at different applied strains and processing temperatures. Surprisingly, processing at 73% of Mg's melting point accelerated microstructural refinement and improved homogeneity, leading to a three-fold increase in hardness compared to ambient processing. This suggests that further optimization could potentially create Mg-based materials with strength beyond a gigapascal.