相场法研究陶瓷粉末烧结体系的微观组织演变

运用相场模型研究陶瓷粉末烧结过程中晶粒的生长和气孔演化过程。采用一组随时间和空间连续变化的取向场变量和浓度场变量来表征体系微结构,用Ginzburg-Laudau动力学方程和Cahn-Hillard动力学方程分别控制取向场和浓度场变量随时间的演化,并针对不同气相含量下的粉末烧结体系,统计其晶粒生长指数,分析气孔含量对晶粒生长的影响。计算结果表明,当烧结体系中气相含量fc在12%～20%之间变化时,随着气相含量的增加,晶粒生长指数m逐渐增大,即晶粒耦合气孔的生长演化速度随气相含量的增加而降低。计算结果与实验情况吻合。

Phase Field Simulation for Microstructure Evolution of Ceramic Powder Sintering System

The evolution of microstructure of grain and pore growth during powder sintering is studied based on phase field model.The microstructure is described by a continuous composition field and orientation field, of which the evolution is governed by the time-dependent Chan-Hilliard equation and the Ginzburg-Landau equation, respectively.In different pore content sintering systems, the grain growth index and the influence of pore content are statistically analysed in grain growth process. Simulation results show that the grain growth index increases when the pore content ranges from 12% to 20%, and evolution rate of grain coupled pore growth decreases.The calculated result is consistent well with the experimental one.