NiNb金属玻璃原子结构和力学性能的分子动力学研究

Molecular dynamics study of atomic structure and mechanical properties of NiNb metallic glass

采用分子动力学模拟的方法,对不同成分的NiNb合金进行原子结构和力学性能方面的研究。通过对降温过程中玻璃转变温度的变化和高温熔体混合焓、混合熵的变化对比发现,在成分点c_(Ni)=0.65前后,合金表现出截然不同的变化趋势。同时利用双体分布函数,配位数,Warren-Cowley参数,键对分析,准近邻原子等方法对NiNb合金进行原子结构相关分析,发现在c_(Ni)=0.65前后,部分结构参数也表现出不同趋势,说明在此成分点前后,NiNb金属玻璃在原子结构上差异较大。综合热力学和结构参数的变化,c_(Ni)=0.65可能是两个合金体系的分界点,c_(Ni)=0.65之前为Nb基,c_(Ni)=0.65之后为Ni基。最后对力学性能进行了模拟,发现力学性能的表现主要和不同成分下NiNb之间的结合方式相关。此项研究有利于加深对金属玻璃原子结构和力学性能的理解。

In this paper,the atomic structure and mechanical properties of NiNb alloys with different compositions were studied by molecular dynamics simulation.By comparing the change of glass transition temperature with the change of mixing enthalpy and mixing entropy of high temperature melt,it is found that the alloy shows a different trend before and after the component point c_(Ni)=0.65.At the same time,the atomic structure correlation analysis of NiNb alloy was carried out by using the methods of pair distribution function,coordination number,W-C parameter,bond pair analysis,and quasi neighbor atom,etc.It was found that some structural parameters also showed different trends before and after c_(Ni)=0.65,indicating that NiNb metallic glass had great differences in atomic structure before and after this component point.According to the thermodynamic and structural parameters,c_(Ni)=0.65 may be the dividing point of the two alloy systems.Before c_(Ni)=0.65,it is Nb base,while after c_(Ni)=0.65,it is Ni base.Finally,the mechanical properties were simulated,and it was found that the mechanical properties were mainly related to the binding mode of NiNb under different components.This study is helpful to deepen the understanding of the atomic structure and mechanical properties of metallic glass.