433223 Effects of Grain Size Distribution on Creep Damage in Polycrystalline Materials By a Monte Carlo Simulation

Wednesday, November 11, 2015: 4:45 PM
255C (Salt Palace Convention Center)
Juan David Ospina-Correa1, Daniel Alejandro Olaya-Muņoz1, Juan Carlos Castrillon1, Alejandro Toro1 and Juan P. Hernandez-Ortiz1,2, (1)Departamento de Materiales y Minerales, Universidad Nacional de Colombia, Medellin, Colombia, (2)Institute for Molecular Engineering, University of Chicago, Chicago, IL

The effects of grain size distribution on creep damage, induced by abnormal grain growth in polycrystalline materials is investigated using a multi-scale mesoscopic simulation approach. The phenomenological modified-Potts free energy functional is adopted and parametrized to predict grain size distribution and shape. The microstructure's evolution is simulated introducing a constitutive model for grain-boundary diffusion, where the effects of boundary topology and grain growth are analyzed. A hybrid Monte-Carlo and molecular-like dynamics method is developed to account for the slow dynamics. Experimental data, from scanning electron microscope to collect a series of electron backscatter diffraction (EBSD) maps of the microstructure are used to parametrize the free energy functional. The simulations correlate with experimental observations where a decrease grain size leads to higher creep strain rates. In addition, a uniform grain size distribution is associated to higher creep strain rates. The implications for high-temperature plasticity mechanical behaviour are discussed. This kind of mesoscopic simulation approach will be the framework for the study of creep in metals and ceramic materials at high-temperature like thermal barrier coatings used in gas turbines for power generation

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See more of this Session: Thermodynamics of Energy Systems
See more of this Group/Topical: Engineering Sciences and Fundamentals