Paper Title:
Statistical Thermodynamics and Ordering Kinetics of D019-Type Phase: Application of the Models for H.C.P.-Ti–Al Alloy
  Abstract

Using the self-consistent field approximation, the static concentration waves approach and the Onsager-type kinetics equations, the descriptions of both the statistical thermodynamics and the kinetics of an atomic ordering of D019 phase are developed and applied for h.c.p.-Ti–Al alloy. The model of order–disorder phase transformation describes the phase transformation of h.c.p. solid solution into the D019 phase. Interatomic-interaction parameters are estimated for both approximations: one supposes temperature-independent interatomic-interaction parameters, while the other one includes the temperature dependence of interchange energies for Ti–Al alloy. The partial Ti–Al phase diagrams (equilibrium compositions of the coexistent ordered α2-phase and disordered α-phase) are evaluated for both cases. The equation for the time dependence of D019- type long-range order (LRO) parameter is analyzed. The curves (showing the LRO parameter evolution) are obtained numerically for both temperature-independent interaction energies and temperature-dependent ones. Temperature dependence of the interatomic-interaction energies accelerates the LRO relaxation and diminishes a spread of the values of instantaneous and equilibrium LRO parameters versus the temperature. Both statistical-thermodynamics and kinetics results show that equilibrium LRO parameter for a non-stoichiometry (where an atomic fraction of alloying component is more than 0.25) can be higher than for a stoichiometry at high temperatures. The experimental phase diagram confirms the predicted (ordered or disordered) states for h.c.p.-Ti– Al.

  Info
Periodical
Solid State Phenomena (Volume 138)
Edited by
J. Čermák and I. Stloukal
Pages
283-302
DOI
10.4028/www.scientific.net/SSP.138.283
Citation
T. M. Radchenko, V. A. Tatarenko, H. Zapolsky, "Statistical Thermodynamics and Ordering Kinetics of D019-Type Phase: Application of the Models for H.C.P.-Ti–Al Alloy", Solid State Phenomena, Vol. 138, pp. 283-302, 2008
Online since
March 2008
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Guo Xian Liang, Robert Schulz
93
Authors: Tomohisa Kumagai, Shotaro Hara, Satoshi Izumi, Shinsuke Sakai
Abstract:A method for making interatomic potentials is proposed and is applied to Cu-Zr-Hf-Ni- Al bulk-metallic-glass systems. The method consists of...
2123
Authors: V.B. Vykhodets, Tatiana Eugenievna Kurennykh, Aleksandr S. Lakhtin, Anatoly Yakovlevich Fishman
Abstract:The mechanisms of formation of activated states upon diffusion of impurity interstitial atoms in metals have been identified, which allows...
119
Authors: Rodolfo A. Pérez
Abstract:The diffusion process in hcp Zr with low amounts of Fe being in solution or forming very dilute Zr-Fe alloys is analysed and discussed. The...
128
Authors: Jiri Sopousek, Marie Svobodová
Abstract:The paper deals with phase diagram calculations and predictions of selected binary, ternary, and Zr-Nb-O-H quaternary system. These systems...
487