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Role of thermal vibrations in alloy phase transitions

DSpace at IIT Bombay

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Field Value
 
Title Role of thermal vibrations in alloy phase transitions
 
Creator PRASANNA, TRS
 
Subject LONG-RANGE ORDER
TEMPERATURE-DEPENDENCE
BAND-STRUCTURE
BETA-BRASS
ELECTRONIC EXCITATIONS
1ST-PRINCIPLES THEORY
LATTICE-VIBRATIONS
DISORDER
THERMODYNAMICS
SEMICONDUCTORS
order-disorder transitions
alloy phase transitions
electron-phonon interactions
diffraction
 
Description We resolve the fundamental contradiction that has existed from the earliest studies on order-disorder transitions between theoretical models that ignore the effect of thermal vibrations on the chemical interaction parameter, J(0), and the analysis of diffraction data that always incorporates the role of vibrations. New analysis of diffraction data shows that the temperature dependence of the order parameter, the central feature of order-disorder transitions, predicted by existing models is scientifically invalid. All models are constrained by the diffraction data to represent the interaction parameter as J(T) and the ordering energy as temperature dependent. The discrepancy between the experimental and theoretical ordering energies in Ni(3)V and Pd(3)V is direct evidence of their temperature dependence. Thermal vibrations influence order-disorder transitions through both the configurational and vibrational terms and not just the vibrational terms as hitherto believed. A modified Bragg-Williams model is proposed, which is the simplest model whose predicted order parameter can be compared with experiments.
 
Publisher TAYLOR & FRANCIS LTD
 
Date 2012-06-26T09:55:26Z
2012-06-26T09:55:26Z
2011
 
Type Article
 
Identifier PHASE TRANSITIONS,84(2)118-134
0141-1594
http://dx.doi.org/10.1080/01411594.2010.523813
http://dspace.library.iitb.ac.in/jspui/handle/100/14341
 
Language English