Calculation of Glass-Forming Ability in the Ni-Zr and Ni-Ti Systems from Interatomic Potentials

2000 ◽  
Vol 644 ◽  
Author(s):  
W.S. Lai ◽  
B.X. Liu
Keyword(s):  
Solid State ◽  
Solid Solutions ◽  
Amorphous State ◽  
Md Simulations ◽  
Interatomic Potentials ◽  
Glass Forming ◽  
Lindemann Criterion ◽  
Amorphous States ◽  
State Amorphization ◽  
Amorphous Interlayer

AbstractFor the Ni-Zr and Ni-Ti systems, Molecular-dynamics (MD) simulations are conducted to compare the relative stability of the terminal solid solutions versus the corresponding amorphous states as a function of solute concentrations. It turns out that the terminal solid solutions transform into an amorphous state spontaneously when the solute concentrations are beyond the maximum allowable values, i.e. the critical solubilities, determined to be 14 at.% Zr in Ni and 25 at.% Ni in Zr for Ni-Zr system and 38 at.% Ti in Ni and 15 at.% Ni in Ti for the Ni-Ti system, respectively. The glass-forming ranges are therefore deduced to be within the respective critical solubilities, i.e. 14-75 at.% Zr and 38-85 at.% Ti for the Ni-Zr and Ni-Ti systems, respectively, which are compatible with those from experiments and/or from the generalized Lindemann criterion. Moreover, MD simulation also reveals that solid-state amorphization does take place and that the growth of the amorphous interlayer follows exactly a t½ law. Besides, a solubility criterion is proposed that the lower the maximum solid solubility the less stable is the lattice of the metal upon solid-state reaction and it can explain the fact that the growing speed of amorphous interlayer toward Ni (melting point = 1528 K) is greater than that directed to the Zr (2128 K) lattice, while it is smaller than that to Ti (1941 K) side.

Glass-forming ability of the Ni–Zr and Ni–Ti systems determined by interatomic potentials

2001 ◽  
Vol 16 (2) ◽  
pp. 446-450 ◽  
Author(s):  
W. S. Lai ◽  
B. X. Liu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Solid Solutions ◽  
Relative Stability ◽  
Glass Forming Ability ◽  
Dynamics Simulation ◽  
Interatomic Potentials ◽  
Glass Forming ◽  
Critical Concentrations ◽  
Amorphous States

Employing the n-body potentials of the Ni–Zr and Ni–Ti systems, we performed molecular dynamics simulation to study the relative stability of the terminal solid solutions versus the corresponding amorphous states as a function of solute concentrations. The terminal solid solutions transformed into amorphous states spontaneously when the solute concentrations were beyond the maximum allowable values; i.e., the critical solubilities were determined to be 14 at.% Zr in Ni and 25 at.% Ni in Zr for Ni–Zr system and 38 at.% Ti in Ni and 15 at.% Ni in Ti for the Ni–Ti system. The physical implication of the critical concentrations, as well as their correlation with the glass-forming abilities of the Ni–Zr and Ni–Ti systems, is discussed.

Electron-irradiation-induced solid-state amorphization in supersaturated Ni–Zr solid solutions

2011 ◽  
Vol 19 (4) ◽  
pp. 511-517 ◽  
Author(s):  
Takeshi Nagase ◽  
Kazuya Takizawa ◽  
Yukichi Umakoshi
Keyword(s):  
Solid State ◽  
Solid Solutions ◽  
Electron Irradiation ◽  
State Amorphization

High pressure solid state amorphization of Si, Ge and solid solutions Si:GaAs, Ge:GaSb

1994 ◽  
Vol 13 (1-3) ◽  
pp. 47-49 ◽  
Author(s):  
V. V. Brazhkin ◽  
A. G. Lyapin ◽  
S. V. Popova ◽  
R. N. Voloshin
Keyword(s):  
High Pressure ◽  
Solid State ◽  
Solid Solutions ◽  
State Amorphization

scholarly journals Generalized Melting Criterion for Amorphization

1992 ◽  
Vol 291 ◽  
Author(s):  
R. Devanathan ◽  
N. Q. Lam ◽  
P. R. Okamoto ◽  
M. Meshii
Keyword(s):  
Solid State ◽  
Strong Support ◽  
Atomic Displacement ◽  
Mean Square ◽  
Root Mean Square Amplitude ◽  
Embedded Atom ◽  
Average Shear ◽  
Lindemann Criterion ◽  
Dynamics Simulations ◽  
State Amorphization

ABSTRACTWe present a thermodynamic model of solid-state amorphization based on a generalization of the well-known Lindemann criterion. The original Lindemann criterion proposes that melting occurs when the root-mean-square amplitude of thermal displacement exceeds a critical value. This criterion can be generalized to include solid-state amorphization by taking into account the static displacements. In an effort to verify the generalized melting criterion, we have performed molecular dynamics simulations of radiation-induced amorphization in NiZr, NiZr2, NiTi and FeTi using embedded-atom potentials. The average shear elastic constant G was calculated as a function of the total mean-square atomic displacement following random atom-exchanges and introduction of Frenkel pairs. Our results provide strong support for the generalized melting criterion.

scholarly journals Methods of amorphization and investigation of the amorphous state

2013 ◽  
Vol 63 (3) ◽  
pp. 305-334 ◽  
Author(s):  
Tomaž Einfalt ◽  
Odon Planinšek ◽  
Klemen Hrovat
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Infrared Spectroscopy ◽  
Solid State ◽  
Terahertz Spectroscopy ◽  
Amorphous State ◽  
Amorphous Form ◽  
X Ray ◽  
State Amorphization ◽  
Crystalline Hydrates ◽  
And Calorimetry

Abstract The amorphous form of pharmaceutical materials represents the most energetic solid state of a material. It provides advantages in terms of dissolution rate and bioavailability. This review presents the methods of solid- -state amorphization described in literature (supercooling of liquids, milling, lyophilization, spray drying, dehydration of crystalline hydrates), with the emphasis on milling. Furthermore, we describe how amorphous state of pharmaceuticals differ depending on the method of preparation and how these differences can be screened by a variety of spectroscopic (X-ray powder diffraction, solid state nuclear magnetic resonance, atomic pairwise distribution, infrared spectroscopy, terahertz spectroscopy) and calorimetry methods.

The Earliest Stage of the Solid State Amorphization Reaction in the Zr-Co System

1994 ◽  
Vol 343 ◽  
Author(s):  
Ralf Busch ◽  
Frank Gaertner ◽  
Susanne Schneider ◽  
Rüdiger Bormann ◽  
Peter Haasen
Keyword(s):  
Solid State ◽  
Chemical Potential ◽  
Amorphous State ◽  
Atom Probe ◽  
Metastable Equilibrium ◽  
Two Phase ◽  
Probe Field ◽  
Emf Measurements ◽  
Amorphous Phases ◽  
State Amorphization

ABSTRACTBased on atom probe field ion microscopy (AP/FIM) studies, electromotive force (EMF) measurements and CALPHAD calculations we discuss the earliest stage of the solid state amorphization reaction (SSAR) in Zr/Co-layers. The AP measurements show that two amorphous phases are formed at the Zr/Co interface from the early stages of the reaction. The metastable two phase field between these amorphous phases is shown by direct measurement of the chemical potential of Zr in amorphous co-sputtered ZrCo alloys by the EMF method. The comparison between the atom probe data and the CALPHAD calculation shows that the interfaces between the different layers are far away from metastable equilibrium in the beginning of the reaction. The amorphous phase formation at the Zr/Co interface and in the hcp-Zr grain boundary is preceded by a supersaturation of the hep ZrCo solid solution that transforms polymorphically into the amorphous state.

Continuous Amorphization of Zr-Based Alloys by Controlled Mechanical Intermixing

1998 ◽  
Vol 554 ◽  
Author(s):  
G. Wilde ◽  
H. Sieber ◽  
J. H. Perepezko
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Critical Value ◽  
Glass Forming Ability ◽  
Al Alloys ◽  
Al Alloy ◽  
Mechanical Working ◽  
Glass Forming ◽  
Ni Alloys ◽  
State Amorphization

AbstractBinary Zr-(Cu, Ni, Al) alloys were mechanically intermixed by cold-rolling stacks of elemental foils. The results indicate that solid-state amorphization is initiated if the grain size of the Zr-Cu and Zr-Ni alloys falls below a critical value. Amorphization was not observed for the Zr-Al alloy. These results are in accordance to the predictions of a model for solid-state amorphization. The comparison with the results on a quaternary Zr-Cu-Ni-Al alloy indicate the influence of multicomponent alloying on the glass-forming ability of Zr-rich alloys by mechanical working.

Mechanism of Solid-State Amorphization in the Fe-Si-Cu-Mg-O System

2021 ◽  
Vol 316 ◽  
pp. 295-299
Author(s):  
Nikolai N. Nikul'chenkov ◽  
Andrey A. Redikul'tsev ◽  
Mikhail L. Lobanov
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Amorphous State ◽  
Continuous Annealing ◽  
X Ray Diffraction ◽  
Transformation Temperatures ◽  
X Ray ◽  
Heating And Cooling ◽  
Cu Alloy ◽  
State Amorphization

Solid-state amorphization process occurring at 600-1060 °C continuous annealing was observed by non-ambient x-ray diffraction on Fe-3%Si-0.5%Cu alloy surface with MgO as thermostable coating. The phenomenon was occurred at α→γ transformation temperatures (920-960 °C) in a layer consisting of Si solid solution in α-Fe and oxides (MgFe)2SiO4, (MgFe)O, SiO2. Amorphous state remained both during heating and cooling to 20 °C. Simulation for diffusion amorphization of Fe (Si) solid solution was proposed. Mg2Si complexes are reduced from oxides by hydrogen then transfer to solid solution and solid-state amorphization is occurred.

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