COMPARISON AMONG THE GROWTH MECHANISMS OF STACKING-FAULT, TWIN LAMELLA AND SCREW DISLOCATION - A MONTE-CARLO SIMULATION

A computer simulation method is employed to simulate the growth of an fee (111) crystal surface, on which emerged the outcrops of a stacking fault, two types of twin lamella [Nai-Ben Ming and J. Sunagawa, J. Cr ystal Growth 91 (1988) 11] bounded by two partial dislocations and a d ipole screw dislocation, respectively. A comparison is made among the stacking fault mechanism (SFM), twin lamella mechanism (TLM) and screw dislocation mechanism (SDM). It is found that SDM is more active than SFM and TLM at low supersaturation. The values of critical supersatur ation Delta mu/kT under which SDM is more active than SFM or TLM are obtained at different temperatures. Delta mu/kT increases as the temp erature is lowered. For B-type TLM, the effect of the size of the twin ned area on the activity of the defect mechanism is discussed.