【摘要】 采用分子动力学方法对液态金属In的快速凝固过程进行计算机模拟跟踪研究 .运用HA键型指数法和原子成团类型指数法分析了金属原子In的成键类型和形成的原子团簇结构 .发现 :与通常的液态金属 (如Al)相反 ,随着温度的降低 ,二十面体及与二十面体相关的 1 5 5 1键越来越少 ;与四方体 ,六角密堆积相关的 1 4 2 1 ,1 4 2 2和 1 4 31键数目总和变化很小 ;而与菱面体相关的 1 32l,1 31 1 ,1 30 1和 1 2 0 1的数目却随着温度的降低而显著增加 ,逐渐占据优势 .最后形成一种新型的以菱面体结构为主、夹杂着立方体 (fcc ,bcc)、六角密集等团簇结构所组成的非晶态结构 ,而原来在金属Al的非晶态结构中占绝对优势的二十面体及各种类型多面体团簇结构 ,在此已经完全消失 .这正是非晶态金属In的g(r)曲线分裂的第二峰的顺序为前低后高 ,而与非晶态金属Al的g(r)曲线 (其分裂的第二蜂的顺序为前高后低 )明显不同的微观结构上的物理根源更多还原

【Abstract】 A computer simulation tracking study for the rapid solidification processes of liquid metal In system has been performed by means of molecular dynamics method.Using the index method of Honeycutt Andersen(HA)and the cluster bond type index method,the bond types,clusters and cluster configurations of In atoms are analyzed.It has been found that,contrary to conventional metals(such as Al),the relative number of 1551,1541 bond types,related to the icosahedral configuration,is decreased remarkably with decreasing temperature;the total number of 1421,1422 and 1431 bond types,related to the fcc and hcp structures,only changes a little;the total number of 1321,1311,1301 and 1201 bond types,related to the rhombohedral structure,increases remarkably,and then gradually plays a dominant role.Finally,the amorphous structure is formed mainly with rhombohedral structures and mixed up with clusters of cubic(fcc,bcc)and hcp structures.However,the icosahedral and various polyhedra structures,which occupied a dominant position in the previous amorphous structure of metal Al,vanish completely in the present amorphous structure of metal In.This is just the physical origin in microstructure for the obvious difference between the g(r) curves of amorphous In having a splitting second peak with a lower front sub peak and a higher behind one,and the g(r) curves of amorphous Al having a splitting second peak with a higher front sub peak and a lower behind one.更多还原