This special issue of Philosophical Magazine is dedicated to Professor Armen G. Khachaturyan at Rutgers University. It contains 27 articles focusing on various aspects of microstructural evolution in solids to which Armen has made extraordinary contributions over the past five decades.
After receiving his Master Degree in Metal Physics in 1959 from the Moscow Steel and Alloy Institute, Armen started his research career at the Metal Physics Institute of the Central Research Institute for Ferrous Metallurgy in Moscow. Armen received his Ph.D. Degree in 1963 from the Steklov Institute of Mathematics, the Academy of Science of USSR and his Doctor Habilitus in 1971 from the Metal Physics Institute in Kiev. From 1973 to 1986, Armen worked as a senior research scientist at the Institute for Crystallography, the Academy of Science of USSR. During this period of time, Armen was twice invited (in 1976 and in 1978) as a Visiting Professor in the Department of Materials Science and Mineral Engineering at the University of California, Berkeley. From 1986 to 1988, Armen stayed at the Lawrence Berkeley Laboratory in Berkeley, California as a research scientist, which finally led to his immigration to the United States in 1988. After his family immigrated to the United States, Armen joined the Department of Materials Science and Engineering at Rutgers, The State University of New Jersey in 1988 and assumed his current position as State of New Jersey Chair Professor.
Armen has made seminal contributions to various fields of theoretical and computational materials science. The theories that were first introduced or greatly advanced by him include: the concentration waves theory of ordering in substitutional and interstitial alloys and crystal structure formation in ceramics, the microscopic theory of strain-induced interaction in solid solutions, the microscopic theory of crystal lattice site diffusion and short-range order kinetics, the thermodynamic (maximum entropy principle) approach to X-ray crystallography, the micromechanics theory of elastically anisotropic, multi-phase coherent mixtures and structural domains of arbitrary geometry, and the development of coarse-grained mesoscale and nanoscale Phase Field models of microstructure evolution in various material processes. In particular, the concentration waves theory provides a bridge between statistical theory of alloys, their symmetry, thermodynamics and diffraction. The theory was developed in the late 1960s and early 1970s and is now a standard method for theoretical and experimental characterization of atomic rearrangements caused by phase transformations in metal alloys and ceramic systems. The micromechanics theory was developed in 1960s and is now known as Phase Field Microelasticity theory that is the foundation of the Phase Field modeling of microstructure evolution of stress-bearing defects in solids. The Phase Field models have opened opportunities for realistic three-dimensional computer simulation of coherent phase transformations (martensitic, ferromagnetic and ferroelectric transformations, decomposition, and ordering), dislocation plasticity (multi-dislocation dynamics), fracture (multi-crack propagation), and morphological evolution in strained epitaxial films.
The outstanding scientific works of Armen are published in over 180 papers and summarized in two books, and three review articles. In particular, the book “Theory of Structural Transformations in Solids” has had a tremendous impact in the fields of phase transformations and microstructure evolution since its publication in 1983 by John Wiley and Sons. This book was named the Most Outstanding Book in Engineering in the 8th Annual Professional and Scholarly Book Awards, The American Association of Publishers. 25 years after his first publication, Armen's book is still acknowledged as a reference book and has been recently reprinted by Dover publishers.
Armen's many awards include two from the Institute of Crystallography of the Academy of Science of USSR, the Matthias Award from Los Alamos National Laboratory, and the international William Hume-Rothery Award in 2000 from The Minerals, Metals and Materials Society (TMS). He was elected TMS Fellow in 2007.
This special issue of Philosophical Magazine, which has received a tremendous response, owes much to Patrick Veyssière who has initiated the project and has continuously helped during the editing process.