| Abstract: | The thermoelastic martensitic transformation of an equiatomic nickel-titanium alloy is investigated by means of x-ray diffraction motion pictures using synchrotron radiation. The x-ray patterns are recorded by a parallel detector simultaneously in the range of angles 2 =34°–51° at a wavelength of 1.4879 Å during heating and cooling with good temperature resolution. The basic parameters of the attendant B2, R, and B19 phases are determined simultaneously and compared. The variations of the parameters of the martensite B19 unit cell are traced, along with the evolution of the R phase {202}{202} reflection doublet during transformation. Volumetric transformation phenomena are determined, and it is shown that martensite originates in a more unconsolidated structure than in the equilibrium state.Institute of Physics of Strength and Materials Science, Siberian Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 49–54, August, 1994. |
