A PHASE FIELD STUDY FOR SCALING RULES OF GRAIN COARSENING IN POLYCRYSTALLINE SYSTEM CONTAINING SECOND-PHASE PARTICLES

The kinetic scaling of the grain coarsening in the polycrystalline system containing the dispersive second-phase particles were studied by phase field method. The obtained results showed that the increase in the volume fraction of second-phase particles enhanced the growth resistance of grain, resulting in the remarkable deviation of the relationship between the average grain radius R-a and the time t from the non-linear relationship t=AR(a)(m)+B. The kinetic exponent m also increased with the increasing volume fraction of second-phase particles. No matter whether the second-phase particles existed or not in the system studied, the scaling rule had been satisfied at the late stage of grain coarsening. The increase in the volume fraction of the second-phase particles would cause the decrease in the peak value of structure factor profile. When the value of the wave vector k increased to a certain value, the structure factor curve of the studied system was essentially coincident. With the increase in the volume fraction of second-phase particles, The peak values of scaling function decreased and the peak width became wider. According to structure factor and scaling function, it was known that with the increase in the volume fraction of second-phase particles, the interaction among grains weakens and the grain size would become more uniform during the grain coarsening.