Exploiting tube high-pressure shearing to prepare a microstructure in Pb-Sn alloys for unprecedented superplasticity

Superplastic Pb-Sn alloys were produced via tube high-pressure shearing ( t -HPS), in a single step starting from elemental solid bulks. A Pb-40 wt% Sn alloy showed an exceptional superplastic elongation as high ∼1870% at strain rate of 1.0 × 10 −3 s −1 room temperature, thereby elevating the optimum for maximum under these conditions by more than one order magnitude over conventional cast alloys. This unprecedented temperature superplasticity is attributed to equiaxed grains having uniform sizes micrometer, and particular well-mixed domains Pb nearly equal proportions. microstructure cannot be attained eutectic or hypoeutectic through thermomechanical processing , but instead it direct outcome -HPS-generated compositional patterning temperature.