应用基于嵌入原子势函数的分子动力学方法,模拟了嵌入在具有面心立方结构同质块体中的熔融Cu55团簇在不同急冷温度下微观结构的演变情况.通过计算熔融Cu55团簇的均方位移和原子平均能量随时问步的变化,并应用键对分析技术,分析了急冷温度对熔融Cu55团簇结构变化的影响.研究结果表明,由于受到块体结构的影响,在所研究的急冷温度范围内,熔融Cu55团簇在凝固过程中形成了以面心立方结构为主的微观结构.结晶过程是原子不断交换其位置的过程,团簇原子位置的重排敏感于温度的变化.随着急冷温度的升高,原子的扩散范围增大.在100,300和500K三个较低的温度下有利于形成稳定的面心立方结构,但当急冷到100K时,团簇中的原子在没有找到其最佳位置之前就已经完成晶化.在急冷到500K时,团簇中的原子在块体中扩散充分,与块体中的原子形成理想的面心立方结构.在700,900和1100K三个较高的温度上,局域结构表现为随时间步波动性变化.
The structural evolution of a molten Cu55 cluster embedded in face-centred cubic (FCC) bulk is simulated by molecular dynamics method based on the embedded-atom method potential through mean square displacement, pair analysis indices, and the average energy of atoms. The simulated results show that final structure of the embedded Cuss cluster mainly presents local FCC structure at the quenching temperatures. During solidification, the atoms continuously interchange their positions, and the rearrangement of atom positions is sensitive to the temperature change. As the quenching temperature increases, diffusion abilities of the atoms increase. At 100-500 K, the formed FCC structures are stable, whereas at 700-1100 K, the local structures of the clusters fluctuate with time step increasing