Combined modelling and miniaturised characterisation of high-temperature forging in a nickel-based superalloy

Abstract

Continuum models and miniaturised experiments are used to elucidate the high-temperature forgeability of the Ni-based superalloy Inconel 903. Uniaxial compression high temperature tests allow the derivation of an apparent activation energy and the strain rate sensitivity of the deformation process, and to propose a unified constitutive model that captures the underlying physics of deformation. Metallographic analysis is then used to elucidate changes in microstructure which arise during the deformation process; microstructure evolution models which define the changes in grain size and recrystallisation during high temperature compression are proposed. Miniaturised forging experiments in double-cone specimens validate the modelling approach under relevant forging conditions at different temperatures and deformation rates. Finally, the deformation behaviour of this material in an industrially relevant manufacturing scenario – the forging process of a turbine disc – is studied numerically. Keywords: Superalloys, Forging, Process modelling, Continuum plasticity, Turbine discs