Cu-Ni合金结构的分子动力学模拟

采用EAM作用势对Cu-Ni合金的结构特性进行了MD模拟研究.通过FZ结构因子可发现,Cu含量的变化对结构因子的波动影响很小,键取向序参数和键对也表现出相似的变化规律,这表明液态Cu-Ni合金对成份变化不敏感,体系中的化学序较弱.将Cu70Ni30合金熔体的FZ结构因子与Waseda的实验结果进行对比,发现二者吻合得较好,表明EAM势可以很好地描绘Cu-Ni合金的结构特性.在快速冷却过程中,除了Cu20Ni80合金外,其他合金成份的双体分布函数的第二峰都发生了劈裂,标志着体系最终形成了非晶结构,而Cu20Ni80合金的双体分布函数却表现出晶体峰的特征.通过对键取向序参数、键型指数以及铜镍原子的有效扩散系数的分析表明,在快速冷却过程中,Cu20Ni80合金最终形成了hcp晶体结构.

Molecular Dynamics Simulation on Structures of Cu-Ni Alloy

Structural properties of Cu-Ni alloy are studied using MD simulation with EAM potential function. The FZ partial structure factor exhibits that Cu content has a small effect on it and the same holds true for bonded pairs and bond orientation order parameters, which indicates that the structure of Cu-Ni alloy isn't sensitive to its component. FZ partial structure factor of liquid Cu-Ni alloy is compared with that from Waseda, and they agree well with each other, which shows that EAM potential function can correctly describe the structural properties of Cu-Ni alloy, and also that the results of our MD simulation are reliable. In rapid cooling process, the second peaks of their pair distribution function from other Cu-Ni alloy split in two, indicative of amorphous structure; while the pair distribution function of Cu-Nim alloy exhibits the characteristic of crystalline. The bonded pairs, bond orientation order and effective diffusion coefficient of Cu-Ni alloy show that Cu-Ni alloy form shep crystalline at rapid cooling process.