Towards a Predictive Theory of Grain Growth: Experiments and Simulations

A grand challenge problem in engineering of polycrystals is to develop prescriptive process technologies capable of producing an arrangement of grains that provides for a desired set of materials properties. One method by which the grain structure is engineered is through grain growth or coarsening of a starting structure. Grain growth can be viewed as the evolution of a large metastable network, and can be mathematically modeled by a set of deterministic local evolution laws for the growth of an individual grain combined with stochastic models to describe the interaction between grains. Thus, to develop a predictive theory, investigation of a broad range of statistical measures of microstructure are needed and must be obtained using experiments, simulations, data analytics and mathematical modeling. We will present results of both in-situ and ex-situ experiments of grain growth in thin films, which are used as the experimental test bed. One important advantage of thin films is the ability to combine in-situ examination of the motion of boundaries with periodic freezing of the structure to map and quantify statistically significant populations, before reheating to promote continued grain growth. The experimental results will be compared and contrasted with results of sharp and diffuse interface simulations.