Study of the Peculiarities of the Zn-Mn Phase Diagram and Their Effect on the Superplastic Behavior of Fine-Grained Zn-Mn Alloys

The part of binary manganese-zinc phase diagram (alloys containing up to 2% manganese) is analyzed and the expected compositions with increased plasticity are determined in this paper. A special attention is paid to the relation between the composition, microstructure, strain rate, and plasticity of the studied alloys. The mechanical behavior during plastic deformation is analyzed and the domains of strain rate are determined, where a superplastic deformation is expected. Superplastic deformation activation energy of the studied alloys is determined on the basis of the Arrhenius theory equation. It was found that the creep deformation of Zn-0.7% Mn alloy follows the power law, or is controlled by diffusion in grain boundaries, i.e., mechanism of deformation is Coble creep, while the deformation of Zn-1.2% Mn alloy is very low and does not correspond to any of diffusion processes in Zinc.