First-Principles Approach to Ordering and Clustering Behavior in Metallic Alloys: Application to Al-Li and Ni-Mo Systems
The thermodynamic stability/metastability/instability of an alloy system with respect to short- and long-wavelength (ordering and clustering) concentration fluctuations has been studied using the free energy models viz. the ‘static concentration wave’ model and the ‘cluster variation method’. The input to these statistical mechanics based models, viz. the effective cluster interactions, have been provided by using first-principles ‘tight-binding linear muffin-tin orbital’ method in conjunction with (a) the ‘inversion method’ and (b) the ‘augmented space recursion — orbital peeling’ technique. The above methodology has been employed to study the precipitation of δ’ — Al3Li phase from the disordered Al-Li alloys and also to study the ordering reactions in Ni-Mo alloys which involves a number of fcc-based ordered superstructures competing for precipitation.
KeywordsNear Neighbor Cluster Variation Method Free Energy Model Near Neighbor Pair Effective Cluster Interaction
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- 1.W.A. Soffa and D.E. Laughlin, in Physical Properties and Thermodynamic Behaviour of Minerals, NATO ASI series C, Vol. 225, 213 (1988).Google Scholar
- 2.J.P. Simmons, Ph.D. Dissertation, Carnegie Mellon University, USA, (1992) and references therein.Google Scholar
- 4.V. Kumar, O.K. Andersen and A.Mookerjee (eds.), in Methods of Electronic Structure calculations, (World Scientific, Singapore, 1994) and references therein.Google Scholar
- 5.W. Connolly and A.R. Williams, Phys. Rev., B27, 5169 (1983); and in The electronic structure of complex systems, (eds.) W. Temmerman and P. Phariseau, (Plenum Press, New York, 1984) p. 581.Google Scholar
- 6.A.G. Khachaturyan, Theory of Structural Transformations in Solids, (Willey, New York, 1983).Google Scholar
- 7.T. Morita, M. Suzuki, K. Wada and M. Kaburagi (eds.), Progress in Theoretical Physics, Suppl. No. 115, (1994).Google Scholar
- 8.T.H. Sanders Jr. and E.A. Starke Jr. (eds.), Aluminium — Lithium Alloys (New York: The Metall. Soc. A.I.M.E., 1981).Google Scholar
- 9.T.H. Sanders and E.A. Starke (eds.), in Aluminium-Lithium Alloys V, Proceedings of the Fifth International Aluminium-Lithium Conference, Materials and Component Engineering Publications Ltd., ( Williamsburg, VA, 1989 ).Google Scholar
- 13.R. Nozato and G. Nakai, Trans JIM, 18, 679 (1977).Google Scholar
- 14.J.S. Garland and J.M. Sanchez, in Kinetics of Ordering Transformations in Metals, (eds.) H. Chen and V.K. Vasudevan, (TMS Publication, Pennsylvania, 1992) p. 207.Google Scholar
- 19.A. Arya, G.P. Das, S. Banerjee and M.J. Patni, J. Mater Res., (Communicated) (1997).Google Scholar
- 20.A. Arya, S. Banerjee, G.P. Das, T. Saha, I. Dasgupta and A. Mookerjee, Solid St. Phys. (India), 39(C), 358 (1996); and details are to be published.Google Scholar