Partial structure investigation of the traditional bulk metallic glass Pd40Ni40P20

Abstract

Local structures of Pd40Ni40P20 bulk metallic glass (BMG) were investigated by combining anomalous x-ray scattering close to the Pd and Ni K absorption edges, x-ray diffraction, neutron diffraction, and reverse Monte Carlo modeling, from which partial structure factors Sij(Q) and partial pair distribution functions gij (r) as well as three-dimensional atomic configurations were carefully obtained around the constituent elements. A disagreement is found in the local structures with an ab initio molecular dynamics simulation by Guan et al., i.e., the existence of the P-P nearest neighboring configurations is clarified in the present experimental result. From the Voronoi tessellation analysis, a preference of the pure icosahedral configurations is observed around the Ni atoms, whereas the local configurations around the Pd and P atoms are rather distorted icosahedra. A persistent homology analysis was carried out to identify meaningful shape characteristics of the intermediate-range atomic configuration of large rings.

Bridging Structural Inhomogeneity to Functionality: Pair Distribution Function Methods for Functional Materials Development

“…With regard to this, the large‐box RMC simulation could be the only method of choice to feedback an amorphous structural model from the PDF data. The first RMC modeling of amorphous SiO 2 was performed in 1990, [ 138 ] and since then the algorithm has been optimized significantly, capable of combining MD and DFT, and triggered the RMC studies in a variety of amorphous systems such as metallic glasses, [ 139 ] hydrated complexes, [ 69 ] SiO x , [ 79 ] amorphous MOFs, [ 140 ] porous carbon, [ 141 ] and so on. Despite the above success, nonetheless, this method is frequently questioned as to whether the PDF data itself can carry such a huge information about every random atomic position in an amorphous system, and whether the retrieved chemical or topological results are model‐independent.…”

Impact of Severe Deformation by HPT at Room Temperature on the Relaxation of the Glassy and the Supercooled Liquid States of PdNiP

“…Thus, the differential signal ∆V(k, R= 2.8 nm) affords a discrimination into two different MRO types dominant at different k-values, i.e. k = 5.3 nm −1 -"icosahedral-like" and k = 4.5 nm −1 -"crystal-like" for NiP [56][57][58] and PdNiP [59][60][61] . With respect to the "crystal-like" regime, it should be noted that the presence of nano-crystals is excluded since all NBDPs exhibit only speckle patterns 29,62 for all six sample states, i.e.…”

Revealing hidden medium-range order in amorphous materials using topological data analysis

“…Generally, the application of persistent homology to amorphous MRO structures is challenging, as the definition of characteristic regions (i.e., groups of loops) adopted in the original studies (20)(21)(22)(23)31) is not unique; that is, they use an "optimal cycle" for the geometric characterizations. Here, we introduce a self-consistent and rigorous definition of characteristic regions by separating them according to the number of contained atoms (see below for definitions).…”