Development of a microstructure-sensitive design tool for high temperature strain rate sensitive flow stress of IN100 Ni-base superalloy

A physics based microstructure-sensitive design tool that predicts the flow stress of an IN100 superalloy as a function of temperature and strain rate was developed. The model calibration/validation included new experimental data of strain-rate sensitive high temperature flow stress data obtained on an IN100 alloy with a novel microstructure of coarse-grains that include grain boundary primary precipitates of Ni3Al(γ′), intragranular coarse secondary γ′ and a high volume fraction of coarse tertiary γ′. The model was realized by extending prior work on an athermal yield model developed using discrete dislocation dynamics simulations along with prior literature data on standard microstructures of IN100. The thermally activated component of the yield model was obtained by including an yield stress dependent creep model formulated originally by Wilshire and Scharning (2009) [1], and by invoking a temperature dependent Anti-Phase Boundary (APB) energy based on a formalism that captures high temperature order parameter of Ni3Al. The resultant model was found to capture experimental data on flow stress from current work in addition to reported data on IN100, including the standard subsolvus and supersolvus heat treat conditions.