Coarse-graining approaches in materials systems undergoing coarsening Maria Emelianenko George Mason University When microstructure of polycrystalline materials undergoes coarsening driven by the elimination of energetically unfavorable crystals, a sequence of network transformations, including continuous expansion and instantaneous topological transitions, takes place. This talk will be focused on recent advances related to the multiscale modeling of this process. Two types of approaches will be discussed, one aimed at simulating the evolution of individual crystals in a 2-dimensional system via a vertex model focused on triple junction dynamics, and another one providing Boltzmann-type kinetic model of the evolution of probability density functions associated with crystal misorientations (MDFs). The predicted MDF evolution based on the new kinetic mesoscale model will be discussed and contrasted with those obtained by large-scale phase field, MC and vertex simulations for several classes of interfacial energies. Joint work with I. Yegorov, C. Torres and D. Golovaty