Research On Microstructure And Deformation Mechanism Of Annealed Zr Based Amorphous Alloy

Exploring amorphous alloys is important in the development of new alloys.Due to the preparation conditions of rapid cooling,amorphous alloys are metastable and thermodynamically nonequilibrium.Amorphous alloy is a kind of metallic material,but it also has glass structure characteristics,and has unique physical,chemical and mechanical properties,so it has a wide application prospect in many industries.However,the deformation mechanism has not been completely explained,which restricts the improvement of its mechanical properties.In this work,we selected Zr₂Cu amorphous alloys to investigate the effects of annealing below glass transition on the microstructure and mechanical properties of amorphous alloys,by synchrotron radiation technique and molecular dynamics simulation.Based on the atomic structure change of annealed Zr₂Cu amorphous alloy obtained by synchrotron radiation technique,the structure model of Zr₂Cu amorphous alloy was established by molecular dynamics simulation and annealed under glass transition temperature.It is found that the free volume of the annealed model is reduced,the annihilation of free volumes leads to more dense packing of atoms.The free volume content is linearly related to annealing temperature,and the slope of this linear relationship is affected by annealing time.In order to further investigate the effect of annealing treatment on the mechanical properties of Zr₂Cu amorphous alloys,tensile deformation of the prepared and annealed models was carried out.It is found that the free volume redistributes with local atomic structure rearrangement during annealing,which affects the development of shear band.The yield strength of annealed Zr₂Cu amorphous alloy enhanced with the increasing of annealing temperature.Meanwhile,the variation of free volume with strain is relative,in the elastic stage,the free volume content increases linearly with the strain,while in the plastic stage,the free volume content increases slowly.The free volume content of the model annealed at different temperatures finally converges to the same region,indicating that annealing has no obvious effect on the free volume of amorphous alloy during the quasi-static flow stage.