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为预测合金介观组织的形成与演变,提出了改进的三维元胞自动机(CA)模型。该模型采用枝晶形状函数,简化描述介观区域的枝晶生长轮廓;利用基于Eu ler角的空间坐标转换,描述随机晶向的多晶粒生长;采用H ash表加速算法,耦合了溶质场计算,采用数值算法处理固液界面的溶质再分配。该模型可模拟大范围随机取向的多晶粒生长过程,并具有较高的计算效率。结果表明:不同模拟区域和网格剖分尺寸对晶粒体积的分布规律没有明显影响;较快冷却速度下,存在溶质富集和枝晶偏析。对A l4Cu合金的砂型和金属型试样的显微组织分别进行模拟,结果与实验符合较好。
In order to predict the formation and evolution of the alloy mesophase, an improved three-dimensional cellular automata (CA) model is proposed. In this model, the dendritic shape function is used to describe the dendrite growth profile of the mesoscopic region. The Euler angle-based spatial coordinate transformation is used to describe the growth of random grains in the multi-grain growth. The Hash table acceleration algorithm is used to couple the solute field Calculations, using numerical algorithms solute solute redistribution at the solid-liquid interface. The model can simulate a large range of randomly oriented multi-grain growth process, and has a high computational efficiency. The results show that the distribution of grain size has no obvious effect on the distribution of grain size in different simulated areas and meshed size. Under faster cooling rate, solute enrichment and dendritic segregation exist. The microstructures of the sand and metal specimens of A14Cu alloy were simulated respectively and the results were in good agreement with the experiment.