非晶Cu形成过程及其力学性能的微观机理研究

用分子动力学方法模拟了非晶Cu的形成过程,研究了非晶Cu力学性能的微观机理.用径向分布函数(RDF)和键对分析方法(PA),分析了快速冷却过程中系统内部结构的变化.非晶Cu径向分布函数第2个峰有明显的劈裂,键对分析表明,在快速降温过程中2331,2211和2101键对的增多是径向分布函数第2峰劈裂的原因.对非晶Cu进行拉伸、剪切加载模拟,结果表明,非晶Cu应力达到最大值之后,没有应力值的突降,宏观上出现类似塑性变形的行为.但是,非晶金属变形的微观机理不同于晶体.本文引入微观数密度统计分析,发现加载过程中微观密度呈现非均匀演化,这为理解宏观类似塑性行为的微观机理提供了线索和可能的分析方法.

Microscopic study of formation and mechanical properties of amorphous Cu

The microscopic mechanism of the formation and mechanical behavior of amorphous Cu were studied by using molecular dynamics simulation method.The radial distribution function(RDF) and the pair analysis(PA) technique were used to characterize the structure of Cu during solidification.The splitting of the second peak of the RDF in amorphous state,is caused mainly by the increase of 2101,2211,2331 pairs.Simulations of tension and shear tests show that the deformation of the amorphous Cu is similar to that of crystalline metals.However,the microscopic mechanism of deformation of amorphous metal is different from that of crystals.In order to understand the microscopic mechanism,the statistical evolution of microscopic number density was analyzed.It was found that the evolution of microscopic density presents inhomogeneity,which may play an important role in the deformation.