Microstructural evolution of inconel* 718 during ingot breakdown: process modelling and validation

摘要

A computer model is presented thatdescribes microstructural evolution during the ingotbreakdown of nickel base superalloy Inconel 718 viathe open die cogging operation. To support thedevelopment of the model, a compression testingprogramme has been carried out which covers theranges of temperatures, strains, and strain ratesexperienced during thermomechanical processing.Analysis of the flow curves has allowed theidentification of the regimes in which the variousdeformation mechanisms take place. Logic based ruleshave been incorporated into the model, and this hasallowed predictions of the microstructural evolution tobe made. Where possible, the results have beencompared with the available experimental data and it isshown that theory and experiment are in reasonableagreement. A number of computational experimentshave been carried out, to study the effects of changing theforging procedure.