搅拌铸造SiCp/Al-7.0%Si复合材料的三维微观组织模拟

对搅拌铸造法制备SiC颗粒（SiCp）增强Al-7．0％Si（质量分数）复合材料的微观组织形成过程进行了模拟研究，建立了常规凝固条件下相应的宏观传热、等轴枝晶形核、生长以及颗粒推移的三维计算模型，采用一种改进的CA（cellular automaton）方法与有限差分法耦合进行数值计算，研究了不同颗粒体积分数对复合材料宏观传热、微观组织以及颗粒分布的影响．为了验证模拟结果，浇注了阶梯形金属型和砂型试样．结果表明，模拟得到的复合材料颗粒分布及微观组织与实验结果吻合良好．随着颗粒体积分数的增加，凝固时间逐渐缩短，基体晶粒逐渐细化，颗粒分布趋向均匀．

3D MICROSTRUCTURE SIMULATION OF Al-Si/SiCp COMPOSITES FOR STIR CASTING

The microstructure of SiC particle reinforced A1-7.0%Si (mass fraction) composite prepared by stir casting was simulated by a modified cellular automaton method coupled with finite difference method,and 3D mathematical and numerical models under normal solidification condition were established including macro heat transfer,nucleation,equiaxed dendrite growth and particle pushing.The effects of particle volume fraction on macro heat transfer,composite microstructure and particle distribution were studied.The simulated results can clearly show the evolution of the microstructure of composite and particle clustering phenomena caused by particle pushing,which are in good agreement with the experimental ones.With the increase of SiC particle volume fraction, solidification time is decreased,composite matrix grains are refined and particles distributed more uniformly.