Experimental andab initiomolecular dynamics simulation studies of liquidAl60Cu40alloy

Abstract

X-ray diffraction and ab initio molecular dynamics simulation studies of molten Al 60 Cu 40 have been carried out between 973 and 1323 K. The structures obtained from our simulated atomic models are fully consistent with the experimental results. The local structures of the models analyzed using Honeycutt-Andersen and Voronoi tessellation methods clearly demonstrate that as the temperatures of the liquid is lowered it becomes more ordered. While no one cluster-type dominates the local structure of this liquid, the most prevalent polyhedra in the liquid structure can be described as distorted icosahedra. No obvious correlations between the clusters observed in the liquid and known stable crystalline phases in this system were observed.

Structural origin of the pinpoint-composition effect on the glass-forming ability in the NiNb alloy system

“…32 As shown in Fig. 4, many Ni and Nb atoms in all the samples are prone to be centered in some icosahedrallike VCs, such as those indexed as ,0,2,8,2., ,0,3,6,3., and ,0,1,10,2..…”

“…25,31 Subsequently, the simulated atomic structural models were further analyzed by the Voronoi tessellation method. 31,32 The RMC simulation is an iterative method extensively used for building the possible structural models for probing structural information in disordered systems that agree quantitatively with the available experimental data (such as the synchrotron radiation-based x-ray diffraction, EXAFS, and neutron diffraction data). In particular, it is available for glassy alloys.…”

Detecting Structural Features in Metallic Glass via Synchrotron Radiation Experiments Combined with Simulations

“…Because all the XRD and EXAFS should be fitted well with all the corresponding theoretical counterparts calculated from the same structural model, such constraint confirms the reliability RMC of the simulation. Additionally, the simulated structural models were further analyzed by the Voronoi tessellation method [23,25]. According to the Voronoi original algorithm, each convex Voronoi polyhedron (VP) can be built by connecting the perpendicular bisectors between a center atom and all of its neighboring atoms.…”

“…Each VP may be indexed as <n3,n4,n5,n6,…>, where ni denotes the number of i-edged faces on the surface of this polyhedron. Each VP should be embedded in a corresponding convex Voronoi cluster (VC), which is made up of one center atom and its neighboring shell atoms [25,29]. Thus, Σni also stands for the number of the shell atoms in one VC, i.e., the coordination number (CN) of the center atom.…”

“…In order to obtain the atomic structural information as reliably as possible, both the normalized diffraction and EXAFS data were simulated simultaneously under the framework of reverse Monte-Carlo (RMC) [25]. The RMC simulation technique is an iterative method for building a structural model in disordered systems with detailed structural information that agrees quantitatively with experimental data (such as the synchrotron radiation-based XRD, EXAFS, and neutron-diffraction data) [26].…”