Short Range Order Modeling in Alloys

Mapping Intimacies ◽

10.31219/osf.io/sw6xp ◽

2021 ◽

Author(s):

Edward Kremer

Keyword(s):

Phase Transition ◽

Short Range ◽

Short Range Order ◽

Statistical Thermodynamic ◽

Short List ◽

Model Cluster ◽

Combinatorial Factor ◽

Associated Solution Model ◽

Associated Solution ◽

Advanced Version

The Short and Long Range Orders in alloys can be considered based on a new expression for the combinatorial factor. This expression is more convenient and intuitive than the traditionally used form and can be directly applied to reproduce the results of several good known statistical-thermodynamic models that usually are considered completely independent or even inconsistent.The short list includes quasichemical theory, associated solution model, surrounded atom model, cluster site approximation.As result, the formalism and interpretation of these models are significantly clarified, allowing simultaneously to identify and fix several long standing errors that otherwise could be left unnoticed.Multicomponent generalization of listed models is also critically simplified.For the systems experiencing a phase transition, the advanced version of theory provides a mechanism allowing to reproduce the correct critical temperature of conversion and at the same time to increase significantly the precision of thermodynamic functions.

Download Full-text

Concentration Fluctuation in Long Wavelength Limit in Liquid Magnesium Alloy

Himalayan Physics ◽

10.3126/hj.v2i2.5211 ◽

2011 ◽

Vol 2 ◽

pp. 47-49

Author(s):

D Adhikari ◽

B. P. Singh ◽

I. S. Jha

Keyword(s):

Order Parameter ◽

Short Range ◽

Short Range Order ◽

Wave Length ◽

Concentration Fluctuation ◽

Chemical Order ◽

Long Wavelength ◽

Long Wave ◽

Associated Solution Model ◽

Associated Solution

The microscopic structure of MgSn liquid alloy at 1073K has been studied by using regular associated solution model. For this we have calculated the concentration fluctuation in long wave length limit [SCC(0)] and chemical short range order parameter (α1) of liquid MgSn alloy at 1073 K.Keywords: Binary Alloy; Complex; Chemical order; Microscopic FunctionThe Himalayan Physics Vol.2, No.2, May, 2011Page: 47-49Uploaded Date: 1 August, 2011

Download Full-text

Pb()O3-type Perovskites: Part I. Pair-correlation Theory of Order-disorder Phase Transition

Journal of Materials Research ◽

10.1557/jmr.1997.0284 ◽

1997 ◽

Vol 12 (8) ◽

pp. 2117-2126 ◽

Cited By ~ 11

Author(s):

Hyun M. Jang ◽

Su-Chan Kim

Keyword(s):

Long Range ◽

Order Parameter ◽

Short Range ◽

Short Range Order ◽

Pair Correlation ◽

Range Order ◽

Statistical Thermodynamic ◽

Range Order Parameter ◽

Long Range Order ◽

Short Range Order Parameter

The limitation of the long-range order parameter and the necessity of the short-range order parameter for the thermodynamic description of Pb()O3-type perovskites are discussed. Based on the discussion, a statistical thermodynamic model that takes into account the configuration of the neighboring B-site ions (B′ and B″ cations) was developed. A pair-correlation approximation was used in the calculation of the configurational entropy and the long-range coulombic interaction energy between the nearest B-site ions. The theoretical calculations using Pb(Sc1/2Ta1/2)O3 (PST) and Pb(Sc1/2Nb1/2)O3 (PSN) systems indicate that the short-range order parameter persists over a wide range of temperatures examined (0–1800 K) and that there possibly occur consecutive long-range order-disorder transitions in the configuration of B-site cations. The possibility of the existence of short-range ordering above the long-range order-disorder transition temperature was also examined using the annealed PSN specimen as a typical example of Pb()O3-type perovskites.

Download Full-text

Short Range Order in the Phase Transition of the Si(100) Surface Reconstruction

Ordering at Surfaces and Interfaces - Springer Series in Materials Science ◽

10.1007/978-3-642-84482-9_16 ◽

1992 ◽

pp. 137-143 ◽

Cited By ~ 1

Author(s):

K. Kakitani ◽

A. Yoshimori

Keyword(s):

Phase Transition ◽

Surface Reconstruction ◽

Short Range ◽

Short Range Order ◽

Range Order

Download Full-text

Thermodynamic and structural properties of Mg-Tl liquid alloy

BIBECHANA ◽

10.3126/bibechana.v8i0.5692 ◽

2012 ◽

Vol 8 ◽

pp. 81-89 ◽

Cited By ~ 1

Author(s):

BP Singh ◽

D Adhikari ◽

IS Jha ◽

BC Kumar ◽

SK Chaudhary ◽

...

Keyword(s):

Short Range ◽

Enthalpy Of Mixing ◽

Mixing Enthalpy ◽

Mixing Properties ◽

Long Wavelength ◽

Energy Of Mixing ◽

Chemical Complex ◽

Free Energy Of Mixing ◽

Associated Solution Model ◽

Associated Solution

The concentration dependent asymmetry in mixing properties of Mg-Tl liquid alloys at 923 K has been investigated on the basis of regular associated solution model. The concentration of ApB type complex in a regular associated solution of Mg and Tl have been determined. We have then used the concentration of complex to calculate the free energy of mixing, enthalpy of mixing, entropy of mixing, activity, concentration fluctuations in long wavelength limit SCC(0) and the Warren Cowley short-range parameter 1 α .The analysis suggests that heterocoordination leading to the formation of chemical complex Mg2Tl is likely to exist in the melt. The analysis reveals that there is a tendency of unlike atom pairing (Mg-Tl) in Mg-Tl alloy whole range of concentration.Keywords: Mg-Tl alloy; microscopic structure; pairwise interaction energy; chemical short range orderDOI: http://dx.doi.org/10.3126/bibechana.v8i0.5692BIBECHANA 8 (2012) 81-89

Download Full-text

Antiferroelectric phase transition in titanite: Excess entropy and short range order

American Mineralogist ◽

10.2138/am-2000-0417 ◽

2000 ◽

Vol 85 (3-4) ◽

pp. 557-562 ◽

Cited By ~ 16

Author(s):

Stuart A. Hayward ◽

Jaime del Cerro ◽

Ekhard K.H. Salje

Keyword(s):

Phase Transition ◽

Short Range ◽

Short Range Order ◽

Excess Entropy ◽

Range Order ◽

Antiferroelectric Phase

Download Full-text

OBSERVATION OF PHASE TRANSITIONS AT THE (100) SURFACE OF Al-3 at.% Ag

Surface Review and Letters ◽

10.1142/s0218625x95000133 ◽

1995 ◽

Vol 02 (02) ◽

pp. 141-145 ◽

Cited By ~ 1

Author(s):

E. WETLI ◽

M. HOCHSTRASSER ◽

D. PESCIA ◽

M. ERBUDAK

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Photoelectron Spectroscopy ◽

Short Range ◽

Short Range Order ◽

Elevated Temperatures ◽

X Ray ◽

First Order ◽

First Order Phase Transition ◽

First Order Phase

In the bulk binary alloy Al-3 at.% Ag , Ag 2 Al precipitates are formed below 410°C which are reversibly dissolved at elevated temperatures. We have followed this phase transition at a (100) surface as a function of temperature by monitoring the bandwidth of the Ag 4d states in X-ray photoelectron spectroscopy. Since the bandwidth measures the coordination number of the emitting atoms, it directly reveals the short-range order of the Ag atoms at the surface. The measurements show that the dissolution of the Ag -rich clusters starts at temperatures at least 100 K below the bulk transition, and the observed hysteresis behavior is indicative of a first-order phase transition at the surface.

Download Full-text