Fifth European Symposium on Martensitic Transformations and Shape Memory Alloys

J. Phys. IV France 11 (2001) Pr8-31-Pr8-35
DOI: 10.1051/jp4:2001805

Precursor phenomenon on TiNi R phase transformation by X-ray diffraction

T. Ohba^{1, 2} and Y. Miyata<sup>3, 4

1</sup>  Department of Materials Science and Engineering, Teikyo University, Utsunomiya 320-8551, Japan
²  Department of Materials Science, Shimane University, Nishikawatsu, Matsue 690-8504, Japan.
³  Department of Environmental and Material Engineering, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan
⁴  The Graduate University of Advanced Studies, Tsukuba 305-0801, Japan.

Abstract
TiNi alloy system has been widely used for industrial application and fundamental research. Many studies were performed under circumstance that R phase was not certainly established. Recently R phase was established and structure of R phase was determined. Present study reports diffuse scattering study as a precursor phenomenon to R-phase by using four-circle diffractometer under circumstance that the structure was determined. Diffuse scattering was observed around 1/3 of [1 ^-1 0]^* incommensurate position at various temperatures in parent phase. Shift from commensurate position broke symmetry and temperature dependence looked random. FWHM of 1/3 reflections and integrated intensities were measured also in parent phase. FWHM decreased and integrated intensities increased with approaching transformation temperature.

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