Weibull尺寸分布晶粒组织演变的仿真研究

Simulation of evolution from an initial grain structure with Weibull grain size distribution

采用一种改进的Potts模型Monte Carlo算法,对具有Weibull尺寸分布(参数β=3.47)的晶粒组织进行了3D正常晶粒长大过程的仿真研究.仿真结果表明:整个晶粒长大过程遵循抛物线长大规律,晶粒生长指数为0.501,非常接近理论值0.5.晶粒长大过程可分为过渡阶段与准稳态长大两个阶段.Weibull尺寸分布参数β由过渡阶段的3.47逐渐演变为准稳态阶段的2.76,准稳态阶段晶粒尺寸分布参数保持β=2.76不变.晶粒的平均面数〈f〉随仿真时间的增加而增大,在准稳态阶段后期趋近于稳定数值.晶粒面数分布为Lognormal分布,最高频率面数f为10,个体晶粒面数范围为3～43.

Monte Carlo simulations with Potts model were performed to investigate the process of normal grain growth starting from an initial microstructure, the grain size distributions of which could be well described by the Weibull function with a parameter β= 3.47. The result show that a parabolic law is observed in grain growth and the simulation time exponent of grain growth n = 0.501, which is very close to the theoretical value for grain growth n = 0.5, is attained. The complete process of normal grain growth simulation includes transition period and steady state period. In transition period, the grain size distribution is changed rapidly from the Weibull distribution with β = 3.47 to the Weibull distribution with β = 2.76. In steady state period, the grain size distribution maintains the Weibull distribution with β = 2.76. The mean grain face number （f） increases with the increase of time and in the late steady state period （f） approaches soine steady value. The Lognormal function fits the grain face number distribution well and the scope of the individual grain face number is 3 - 43.