Grain refinement and superplasticity of Inconel 718 processed by Multi-Pass High-Pressure sliding

Inconel 718 was successfully processed by multi-pass high-pressure sliding (MP-HPS) for production of ultrafine-grained structures in rods with upsized dimensions. An (UFG) structure an average grain size ~ 140 nm developed through rotation 45°. Tensile testing at 1073 K initial strain rate 2x10-2 s−1 led to superplastic elongations more than 400%. A relation is established between hardness and elongation failure so that it should be possible predict the advent superplasticity only from measurement.