Use of computer simulation to aid the understanding of microstructural changes observed in meat-treated AlN ceramics

A parametric computational study, using the Monte Carlo method, was perform ed to examine the effect of gamma(s1)/gamma(ss) value and Monte Carlo step (MCS) on the key microstructural characteristics of aluminum nitride (AIN)/ yttrium aluminate system. The gamma(s1)/gamma(ss) values studied in the sim ulation ranged from 0.1 to 1.0 and covered the non-wetting and wetting situ ations for this liquid phase sintered material. Grain morphology and contig uity of the resultant microstructures were determined, Validation experimen ts were performed on sintered and heat-treated BIN ceramics to study the ef fect of time, temperature, and grain boundary phase level on the microstruc tural development. In addition to contiguity, dihedral angle and grain boun dary phase chemistry were also measured. The mimicking of experimental and computational results suggested that the remarkable microstructural changes observed during heat treatment at 1800 degrees C might be the result of va riations in the gamma(s1)/gamma(ss) value with temperature. There was also good agreement between the simulated microstructures and the ALN ceramics w ith different liquid phase fractions. Dihedral angle measurements of the ce ramic materials confirmed the appropriateness of the gamma(s1)/gamma(ss) va lues used in the simulation.