Monte Carlo simulation of transformations in SiC

Abstract

The 2H to 6H transformation in SiC occurring just above 1600°C has been simulated using Monte Carlo method. The need for this approach arises because of the limitations of the sequential model employed by earlier workers for the calculation of diffraction effects from close-packed crystals undergoing structural transformations through non-random faulting. It is pointed out that in real situations stacking faults are introduced in a random space and time sequence rather than sequentially from one end of the crystal. It is shown that due to the restrictions on the minimum separation between contiguous stacking faults, a requirement for the formation of the product phase, the transformation comes to an arrest because of the formation of interfaces between independently formed regions of the new phase. The numerically computed intensity distributions along diffuse streaks, obtained by taking Fourier transforms of the pair correlations for the intermediate states of transformation simulated using the random space and time sequence model, show marked departures from those obtained analytically by employing sequential model for configurations near the arrested state.