The Study On Structure And Compressive Mechanical Properties Of Zr₈₅Cu₁₅ Amorphous Alloy By Molecular Simulation

In order to improve the plastic deformation capacity of amorphous alloys in room temperature,the Zr₈₅Cu₁₅ amorphous nanocrystalline alloys were prepared by molecular dynamics simulation in this paper,,and the microatomic structure and mechanical properties of the new materials after crystallization were studied.We studied the microatomic structure of Zr₈₅Cu₁₅ amorphous alloy after crystallization prepared by four different cooling rates(5?10¹¹ K/s?1?10¹² K/s?5?10¹²K/s?1?10¹³ K/s).We use coordination number analysis,bond pair analysis,and the Voronoi polyhedron analysis to study the feature of the structure.We found that the icosahedron structure and the number of clusters of face-centered cubic structure is more when the cooling rate was 5?10¹² K/s,which led to this amorphous nanocrystalline model with the least amount of crystallization phase content.The effect of pressure on the formation of amorphous nanocrystalline alloy was studied by applying different pressure?0?30 GPa?in isothermal annealing.The results showed that the pressure is inhibitory to crystallization in the pressure range of our study.After that,we compared the mechanical properties of amorphous nanocrystalline alloy prepared through two different ways.One way is carrying out an isothermal annealing,and another way is applying pressure when annealing.We found that although the volume fraction of crystallization phase is same but the deformation is more uniform of the model which was applied small pressure?0.5Gpa?.When the pressure is at a high level?5 GPa?,the deformation of the model obtained only under the effect of isothermal annealing?800ps?is more uniform and the mechanical performance is better.The uniaxial compression test results of Zr₈₅Cu₁₅ amorphous nanocrystalline alloys in three specific strain rates showed that when the strain rate were 1?10⁸ s^-1 and 5?10⁸ s^-1,the models which were applied larger pressure?4.5 GPa,8 GPa?during isothermal annealing exhibited good plasticity and the fluctuations of atomic strain are smaller.But when the strain rate was increased to 1?10⁹ s^-1,the model which was applied small pressure?1 GPa?showed the more uniform deformation and better mechanical properties.