The usefulness of electron microscopy for the study of phase transformations is illustrated by means of two case studies. The dehydration reaction of goethite to hematite, as studied by controlled heating in the electron beam, is shown to give rise to a particular microtexture consisting of parallel arrays of internally twinned hematite lamellae separated by voids with a period of approximately 6 nm. An in-situ study of the α-β phase transformation in quartz revealed the existence of an incommensurate intermediate phase which could be fully characterized by TEM as a periodic array of Dauphine-twin-related columnar domains with an equilateral triangular shape and a mesh size of 10 to 30 nm. © 1987.
Van Landuyt, J., Van Tendeloo, G., & Amelinckx, S. (1987). Phase transformations as studied by electron microscopy. Ultramicroscopy, 23(3–4), 371–382. https://doi.org/10.1016/0304-3991(87)90248-8