Molecular Dynamic Simulation Of Microstructures Of Severalmetallic Glasses

The research about Metallic glasses(MGs)MGs is the frontier in condensed matter physics and material physics.Due to their excellent physical,mechanical properties and tremendous potential application value.And these advantages are closely related to their atomistic structure.Despite many previous works have been done on the MGs atomic structures,most of these works are focus on the short range order structure,but on the medium range order structure is still far less understanding.Computational research has played a key role in materials and engineering science,providing atomic-scale details otherwise not accessible in experiments.In this work,we use Molecular Dynamic Simulation method to obtain atomic spatial positions of metallic glasses.In this paper,we focus on the following subjects.Firstly,we systematically investigate the short and medium range structure of Cu₅₀Zr₅₀and Cu₄₅Zr₅₀Al₅.Our aim is to clarify the role of Al in the structure of metallic glasses;Secondly,we explore the influencing factors of different glass-forming ability of monatomic BCC and FCC MGs.The main contents are as following.1.We briefly summarize the development history of MGs,the short and medium range order structure of MGs.Some common structural analysis methods used in simulation,such as Pair distribution function,Voronoi tessellation,Common neighbor analysis and five-fold local symmetry are introduced.2.We systematically investigate the short and medium range structure of Cu₅₀Zr₅₀and Cu₄₅Zr₅₀Al₅.Our results show that Al atoms tend to act as the center of icosahedron(ICO)clusters,and it can remarkably increase the fraction of full ICO.More importantly,Al atoms can significantly facilitate the formation of Bergman medium range order.The enhancement mechanism of Al addition on Bergman medium range order can be explained by its adhesive effect on icosahedral clusters.3.The structure of three monatomic BCC(Ta,Mo and V)and three monatomic FCC MGs(Ag,Al and Au)are systematically investigated,to explore the population of ICO-like,crystal-like and mix-like clusters and its correlation with potential energy.We found that BCC glasses have more ICO-like clusters than FCC glasses,and confirming that the potential energy plays the decisive role on the population of clusters.We also found that the ICO clusters tend to grow into medium range structure in BCC glasses.Our results show the microstructure of several metallic glasses,the related conclusions are helpful to understand the short and medium range structure of metallic glasses,and provides a new thinking to explain the high glass forming ability of metallic glasses.