COMPUTER-SIMULATION OF GRAIN-GROWTH WITH 2ND-PHASE PARTICLE PINNING

The pinning effect of second phase particles on grain growth was simul ated by 2-D Monte Carlo simulations. A new variable, the degree of con tact between grain boundaries and second phase particles, was introduc ed to predict the grain size limit in the presence of second phase par ticles. The modified Zener pinning model containing this new variable can be expressed as: D/r = K/Rf where D is the pinned grain size,, is the mean size of second phase particles, K is a constant, f is the are a fraction (or the volume fraction in 3-D) of second phase, and R is t he degree of contact between grain boundaries and second phase particl es. In 2-D Monte Carlo simulations of grain growth the ratio of pinned grain size to second phase particle size was found to be proportional to f(-0.5), but also to (Rf)(-1). The degree of contact increased dur ing grain growth and reached a stable value when the grain structure w as pinned. The initial location of second phase particles did not have a significant contribution to the pinning of grain boundaries. (C) 19 97 Acta Metallurgica Inc.