NUMERICAL SIMULATION OF MICROSTRUCTURE FOR STIR CASTING OF Al-Si/SiC_p COMPOSITES WITH PARTICLE PUSHING MODEL

摘要

Particle distribution has vital influence on the microstrucrure and the final performance of particle reinforced metal matrix composite. The formation of microstrucrure of SiC particle reinforced Al-7.0wt%Si composite made by stir casting was simulated in this paper. Two-dimensional models under normal solidification condition including macro heat transfer, nucleation, equiaxed dendrite growth and particle pushing were presented. A modified cellular automaton method coupled with finite difference method was used to simulate composite microstrucrure. The effects of SiC particle volume fraction on composite microstrucrure and particle distribution were analyzed. The simulated results can clearly show particle clustering phenomena caused by particle pushing. The final microstrucrure is in good agreement with the experimental results. With the increase of SiC particle volume fraction, composite matrix grains are refined and particles are distributed more uniformly.