The Inner Research Of Correlation Between Microstructure And Mechanical Properties Of Amorphous Zr Base Binary Alloy

MG is a relatively new material that has many potential applications because of itshigh specific strength,high elastic limit, and high restitution coefficient. However,itsplasticity is poor at room temperature. In order to improve plasticity at roomtemperature,we explain the relation between structure and properties of amorphous fromthe atomic level by using molecular dynamics simulation.We use pair distribution function, bond pair analysis, the bond angle analysis and theVoronoi polyhedron analysis to contrast the liquid state and amorphous state. Resultsshow that in the process of cooling, there is competition among icosahedron, defecticosahedron, and face-centered cubic structure. Finally in the amorphous alloy, fivesymmetric structure is dominated.Molecular-dynamics simulations of the deformation behavior of ZrCu metallic glassreveal that plasticity and strength can be effectively improved by pre-introducing shearorigin zones. A local strain region1–2nm in size can be clearly observed. Stronginteractions produced in these shear origin zones lead to uniform strain distribution and tothe avoidance of stress localization. The simulation data well agree with the experimentalresults.The reversible degree of shear origin zones (SOZs) is used as the structural indicatorto distinguish the elastic deformation and inelastic deformation of ZrCu metallic glass. Wefind that the formation of SOZs is reversible at the elastic stage but irreversible at theinelastic stage. At the inelastic stage, the full-icosahedra fraction in SOZs is quicklyreduced with increased strain.The whole process of the formation of shear band is investigated. When the shearband is formed along45°direction, there is strong interaction between the atoms within theshear bands.After that,the direction of atom becomes different. This suggests that thestress concentration in the shear band leads to the instability of deformation andcatastrophic brittle fracture. In the process of cooling,there is reducing in the five symmetric structure of theamorphous. Because this five symmetric structure is the most resistance to form sheartransformation zones,the tensile strength is decreased with increasing cooling rate.