A study of grain growth and microstructure control in silicon nitride by computer simulation

A grain growth simulation technique is developed for microstructure design of ceramic materials by extending the Ports model. The simulation model has successfully reproduced the self-reinforced microstructure which is peculiar to silicon nitride, consists of large elongated grains and small equiaxed grains. To control the microstructure of silicon nitride further, a seeding technique is effective and often employed. Grain growth behavior of seed particles in the simulation is studied. It is found that the seed grains grow with a relatively high growth rate during the early stage of grain growth. In contrast in the later stage, the difference between microstructures with and without seed particles decreases. This behavior agrees well with that of actual silicon nitride. These results demonstrate the consistency of the simulation.