X-Ray Diffraction Studies of the Reversible Phase Transformation in NiTi Shape Memory Alloy
Z. Lekston and M. Zubko
Institute of Materials Science, University of Silesia, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland
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In the present paper the phase transformations occurring in hot worked and heat-treated Ni-rich NiTi shape memory alloy were studied using X-ray diffraction, differential scanning calorimetry and bend and free recovery measurements. Based on conducted measurements it can be seen that in the studied alloy two-step B2 ↔ R ↔ B19' phase transitions occurred. Due to the fact that during heating the phase transition B2 → R and R → B19' occurs in a very narrow temperature range and differential scanning calorimetry peaks overlap additional X-ray diffraction measurements were performed. Obtained characteristic temperatures from applied different experimental methods are in good agreement. The optimum heat-treatment was selected to obtain rods with a shape recovery temperature Af below 37°C to prepare prototypes of medical implants activated by patients body heat.

DOI: 10.12693/APhysPolA.130.1059
PACS numbers: 62.20.fg, 81.30.Kf, 61.05.cp