Hostname: page-component-8448b6f56d-xtgtn Total loading time: 0 Render date: 2024-04-23T09:07:56.647Z Has data issue: false hasContentIssue false
  • English
  • Français

Hallimond Lecture 1970 Electron-Optical study of phase transformations

Published online by Cambridge University Press:  05 July 2018

J. D. C. McConnell
J. D. C. McConnell*
Affiliation:
Department of Mineralogy and Petrology, Downing Place, Cambridge
Get access Rights & Permissions [Opens in a new window]

Summary

This paper is primarily concerned with the interpretation of phenomena associated with phase transformations in single crystals, as observed by current experiments using electron-optical techniques. An analysis of permissible metastable behaviour in such single crystals, in terms of lattice theory, is provided. The dominant role of symmetry in defining the constraints on permissible be-haviour of this kind is explained. The resulting theory indicates that, at low temperatures, permissible thermal fluctuations in local chemical composition, or order, become strongly degenerate and lead to the development of non-Bragg diffraction effects. The theory and practical study of the phenomena by electron microscopy are also described.

The theory of metastable behaviour in a single crystal subject to symmetry constraints is then tested by re-examining the experimental data available for two systems that have been studied recently where such behaviour might be suspected. The first of these concerns the low-temperature behaviour of adularia, and the second deals with incipient exsolution phenomena in the alkali feldspar from a pantellerite. The data in each case appear to be compatible with the general theory proposed. Finally the theory is used to analyse the low-temperature behaviour of the intermediate plagioclase feldspars. In this case the theory indicates that both antiphase phenomena and schiller effects are associated with metastable behaviour in a system subject to strong symmetry constraints at low temperature. The implications of the analysis in relation to peristerite exsolution phenomena are discussed.

Type
Research Article
Information
Mineralogical Magazine , Volume 38 , Issue 293 , March 1971 , pp. 1 - 20
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1971

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bøggild, (O. B.), 1924. K. Danske Vidensk. Selskab, Math-fys. Meddel. 6, no. 3.Google Scholar
Bown, (M.G.) and Gay, (P.), 1958. Zeits. Krist. 111, 1.CrossRefGoogle Scholar
Cahn, (J.W.), 1968. Trans. Met. Soc. A.I.M.E. 242, 166.Google Scholar
Christie, (O.H.J.), 1968. Lithos. 1, 187.CrossRefGoogle Scholar
Christie, (O.H.J.), 1969. Ibid. 2, 285.Google Scholar
Fleet, (S.G.) and Ribbe, (P.H.), 1965. Min. Mag. 35, 165.Google Scholar
Gay, (P.), 1956. Ibid. 31,21.Google Scholar
Korergawa, (M.) and Jagoigzinski, (H.), 1967. Sehweiz. Min. Petr. Mitt. 47, 269.Google Scholar
Krivoglaz, (M.A.) [KpnBorAaa (M. A.)], 1969. Theory of X-ray and Thermal-Neutron scattering by Real Crystals, English trans., New York (Plenum Press).Google Scholar
Mcconnell, (J.O.C.), 1965. Phil. Mag. ser. 8, 11. 1289.Google Scholar
Mcconnell, (J.O.C.), 1966. Abstract, Chemical Soc. International Symposium on Reaction Mechanisms in Inorganic Solids, July 1966. Aberdeen.Google Scholar
Mcconnell, (J.O.C.), 1967. In Physical Methods in Determinative Mineralogy, p. 335, London (Academic Press).Google Scholar
Mcconnell, (J.O.C.), 1969. Phil. Mag. 19, 221.CrossRefGoogle Scholar
Mcconnell, (J.O.C.), 1969. Ibid. 20, 1.195.Google Scholar
Mcconnell, (J.O.C.), 1969. Abstract, Min. Soc. Sept. Meeting, Aberdeen.Google Scholar
Mcconnell, (J.O.C.), and Fleet, (S.G.), 1963. Nature. 199, 586.CrossRefGoogle Scholar
Nissen, (H.E.), 1967. Contr. Min. Petr. 16, 354.CrossRefGoogle Scholar
Nissen, (H.E.), 1968. Sckweiz. Min. Petr. Mitt. 48, 53.Google Scholar
Nissen, (H.E.), Eggmann, (H.), and Laves, (F.), 1967. Ibid. 47, 290.Google Scholar
Weinreich, (G.), 1965. Solids, Elementary Theory for Advanced Students, New York (John Wiley).Google Scholar
Yund, (R.A.) and Mccallister, (R.H.), 1970. Chem. Geol. 6, 5.CrossRefGoogle Scholar
Ziman, (J.M.), 1964. Principles of the Theory of Solids (Cambridge University Press).Google Scholar