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On the problem of fluctuations near first‐order phase transformations in solids
Author(s) -
Cook H. H.
Publication year - 1975
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889875009855
Subject(s) - metastability , phonon , phase (matter) , condensed matter physics , excitation , phase boundary , thermal , boundary (topology) , phase transition , thermal fluctuations , physics , order (exchange) , statistical physics , materials science , thermodynamics , quantum mechanics , mathematics , mathematical analysis , finance , economics
The recent experimental results on the phonon structure of b.c.c. Zr–Nb alloys are reviewed. The central (elastic) phonon peak is discussed in terms of quasi‐static heterophase fluctuations which are postulated to form by thermal excitation to a coherent‐metastable state and to decay by boundary collapse. This concept is extended qualitatively to the problem of fluctuations associated with first‐order compositional transformations – clustering and ordering. It is suggested that quasi‐static fluctuations should also occur near the coherent phase boundary for first‐order compositional transformations. These fluctuations can be properly interpreted as small particles of the low‐temperature phase. The model is used to discuss qualitatively the disorder to long‐period and long‐period to ideally ordered phase transitions.