Simulation Study On Deformation Mechanism And Strengthening Mechanism Of Nanoglass Alloy

Metallic glass has become one of the new generation of high-performance structural materials due to its excellent mechanical properties such as high strength,high hardness and high elasticity.However,due to the lack of long-range ordered structure,metallic glass is prone to local deformation and poor tensile plasticity at room temperature,which seriously restricts its application in various fields.Therefore,it is of great significance to study how to balance the relationship between strength and plasticity of metallic glass.The appearance of nano glass can effectively enhance the plasticity of metallic glass,but the strength of metallic glass is seriously weakened due to the introduction of glass/glass interface.In order to solve this problem,molecular dynamics simulation is used to study the strengthening mechanism of Cu-Zr nanoglass under tensile loading,reveal the influence of Cu content on the glass/glass interface structure of Cu-Zr nanoglass,and analyze the coordination relationship between strength and plasticity of nanoglass during tensile loading.The Cu-Zr nanoglass with high strength and plasticity can be obtained by adjusting the microstructure of the interface.This study provides a theoretical basis for the preparation and design of high performance metallic glass.The main research contents and conclusions are as follows:The effect of Cu content on the mechanical properties and deformation mechanism of single-phase Cu-Zr nanoglass is studied by molecular dynamics simulation.The results show that with the increase of Cu content,the packing density of atoms increases and the bonding strength between atoms becomes stronger,which makes the yield strength and Young’s modulus of single-phase Cu-Zr nanoglass increase.However,the plasticity of single-phase Cu-Zr nanoglass first increases and then decreases,which is caused by the difference of shear deformation resistance between grains and glass/glass interface in single-phase Cu-Zr nanoglass.It is pointed out that the anti-deformation ability between grain and glass/glass interface in single-phase Cu₇₅Zr₂₅nanoglass is relatively high,which makes the two coordinated movement during tensile loading and realizes the effective combination of high plasticity and high strength.In addition,the results show that the single-phase Cu₈₅Zr₁₅nanoglass has the highest strength,but there is a main shear band throughout the sample during deformation,which will lead to catastrophic fracture in the subsequent loading process,so its mechanical properties need to be further improved.The stability of interface structure is closely related to the mechanical properties of materials.In this paper,the effect of interface structure on the strengthening mechanism and deformation behavior of amorphous/amorphous dual-phase Cu-Zr nanoglass is studied.The results show that the mechanical properties of amorphous/amorphous dual-phase Cu-Zr nanoglass are determined by the matrix phase,the second phase and the glass/glass interface.When the Cu content of the second phase is low,the second phase has low deformation resistance,so the plastic deformation of the second phase of the dual-phase nanoglass is dominant in the loading process,and the matrix phase almost does not participate in the plastic deformation,which makes the dual-phase nanoglass enter the yield stage ahead of time with poor strength and plasticity.When the Cu content of the second phase is high,the second phase and the glass/glass interface have high deformation resistance,and the stability of the interface between the matrix phase and the second phase is high.Therefore,in the process of tensile loading,the matrix phase,the second phase and the glass/glass interface move together to achieve the effective combination of strength and plasticity,so as to obtain the Cu-Zr nanoglass with high strength and high plasticity.