Numerical analysis on morphology of second phase particles during grain growth

Uniform microstructure as well as stability of polycrystalline alloys largely depend on the unique motion of grain boundaries during heat treatment. The presence of second phase particles along grain boundaries is widely considered to be one of the most effective mechanisms for stabilizing the polycrystalline structure. With the help of the versatile computational tool, phase field modeling, secondary phase volume fraction, and the morphology of secondary phase precipitates are numerically analyzed. It is found that the migration mechanism of the grain boundary over differently shaped particles is different. As a result, distinct grain distribution and growth rates are observed in the presence of different particle shapes. Size of particles also plays a significant role in controlling grain boundary mobility as larger particles are mostly occupy the triple, quadruple junctions of grain boundary of higher energy and thereby serve as more efficient inhibitors to grain growth. Particle number is highly influential on pinning the grain boundary as well. The results also reveal that it is more difficult for grain boundaries to pass through spheroidal particles of high aspect ratio compared to cuboid or spherical particles, which is why flat type elongated particles are significantly capable of preserving the grain size distribution.