........ published in NEWSLETTER # 54
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........ published in NEWSLETTER # 54
STATICS AND DYNAMICS AND ALLOY PHASE TRANSFORMATION
by Dr. P.E.A. Turchi and Dr. A. Gonis, Lawrence Livermore Laboratory, Livermore /CA (U.S.A.)
The study of phase transformations in substitutional alloys, including order_disorder phenomena and structural transformations, plays a crucial role in understanding the physical and mechanical properties of materials, and in designing alloys with desired technologically important characteristics. Indeed, most of the physical properties, including equilibrium properties, transport, magnetic, vibrational as well as mechanical properties of alloys are often controlled by and are highly sensitive to the existence of ordered compounds and to the occurrence of structural transformations. Correspondingly, the alloy designer facing the task of processing new high_performance materials with properties that meet specific industrial applications must answer the following questions: What is the crystalline structure and the atomic configuration that an alloy may exhibit at given temperature and concentration? Usually the answer is sought in the phase_diagram of a relevant system that is often determined experimentally and does not provide insight into the underlying mechanisms driving phase stability.
The present proceedings (NATO ASI SERIES B319) from a NATO Advanced Study Institute held in Rhodes, Greece, from June 21 to July 3, 1992, focus primarily on the recent experimental, theoretical and computational developments in the study of alloy phase transformations. This collective report is divided into 17 lectures written by experts in their field, and complemented by 40 contributed papers. It provides an in_depth, up_to_date foundation for future work although its tutorial aspect should not be underestimated. The proceedings cover the four following topics: First, on the experimental and phenomenological fronts, the impact of x_ray and neutron diffuse scattering techniques in studying ordering phenomena and atomic displacement fields in alloys, the new developments in the determination of alloy, phase stability by the so_called CALPHAD approach and finally, the rich field of experimental design and processing of stable as well as metastable alloys, including the new class of quasi_crystalline materials, are thoroughly discussed. Second, on the quantum mechanical front, important chapters on the first_principles theories of structural transformation, and of order_disorder transformations in semi_ conducting, sp_bonded, and transition metal alloys are presented. Third, the statics aspect of alloy transformations is described in the context of Monte Carlo simulations and generalized mean field theories. The last chapters deal mostly with the kinetics and dynamics of alloy transformations, and include the simulation of morphology transformations, steady states and microstructural evolution in driven systems as well as first_principles molecular dynamics studies of amorphous and liquid semiconducting alloys.
All major aspects of alloy transformations have been clearly covered in this publication with a comprehensive account of recent advances in the field and a constant effort to put the overall
subject in perspective. For these reasons, this book should definitely be a requisite for physicists, materials scientists, and physical metallugists, and represent a valuable addition to scientific literature in the general field of alloy theory, transformation, and design.
Reference books: A158, B319, C286, E256, E281