Superplasticity from viscous flow in high Pb ternary alloy

Abstract

This work identifies a new superplastic alloy and proposes the responsible phenomenological model for superplastic flow based on mechanical characterization and microstructural observations. 85Pb–10Sb–5Sn exhibited unusual superplastic behavior in that it requires high homologous temperatures to experience superplastic elongations. A characteristic temperature (TGBS), where grain boundary sliding becomes dominant, was found, which differentiates superplastic from non-superplastic flow. The microstructure study revealed that localized viscous flow of the regions at certain grain boundaries and shear interfaces, followed by formation and elongation of amorphous-induced zones, is responsible for superplastic elongations.