Abstract
The nature of the phase transformation to the rhombohedral samarium-type structure was studied in Gd-Ce alloys. The experimental techniques used were electrical resistance measurements, elevated-temperature X-ray diffraction studies, optical metallography, and transmission electron microscopy. Electrical resistance-temperature hysteresis loops were observed in two temperature regions. X-ray studies confirmed that the upper temperature behavior was due to the phase transformation (hcp ⇌ Sm-type or dhcp ⇌ Sm-type). The lower temperature hysteresis loop does not involve a change in crystal symmetry but does coincide with an increased rate in expansion of thea 0 parameter such that the axial ratio becomes essentially constant with temperature. Optical and electron microscopy revealed a morphology of fine parallel bands extending across a grain in a single variant. This is consistent with the transformation plane being the basal plane.
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Formerly on assignment at Oak Ridge National Laboratory.
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Koch, C.C., Mardon, P.G. & McHargue, C.J. A study of the transformation to the samarium-type structure in Gd-Ce alloys. Metall Trans 2, 1095–1100 (1971). https://doi.org/10.1007/BF02664241
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DOI: https://doi.org/10.1007/BF02664241