Understanding and modeling of gain boundary pinning in Inconel718

Abstract : The microstructure stability during d sub-solvus annealing was investigated in Inconel 718 alloy. A reference dynamically recrystallized microstructure was produced through thermomechanical processing (torsion). The reference microstructure evolution during annealing was analyzed by EBSD (grain size, intragranular misorientation) and SEM ( phase particles). Results con rm that, in the absence of stored energy, the grain structure is controlled by the phase particles, as predicted by the Zener equation. If the reference microstructure is strained (e < 0:1) before annealing, then stored energy gradients between grains will induce selective grain growth leading to coarsening. The phenomenon is controlled by the balance of three forces (acting on boundaries migration) having the same order of magnitude: capillarity, stored-energy and pinning forces. All these forces could be modeled in a single framework by the level set method. The rst numerical results demonstrate the capability of the method to simulate 2D Zener pinning. The aim of this paper is to investigate the influence of the distribution of d phase particles and deformation stored energyon the microstructure stability during d sub-solvus annealing.