On Analysis of DSC Curves for Characterization of Intrinsic Properties of NiTi Shape Memory Alloys
A. Ziółkowski
Institute of Fundamental Technological Research, Polish Academy of Sciences, Pawińskiego 5B, 02-106 Warsaw, Poland
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Differential scanning calorimetry is discussed as a tool for characterization of shape memory alloy materials with the example of Ni51at.%-Ti polycrystalline material. Some inconsistencies connected with the differential scanning calorimetry analysis results present in the contemporary literature are indicated, for example large discrepancies in the registered heats of phase transition or differences in registered heats of forward and reverse phase transition, especially in the case of multi-stage phase transition sequences. An attempt is undertaken to explain some of the discrepancies. The overall conclusion from the present work is that forward and reverse sensible heats of phase transition are equal, and discrepancies reported in the literature are artefacts. It is recommended that as a standard practice of differential scanning calorimetry analysis of shape memory alloy materials not only characteristic temperatures but also sensible heat of phase transition should be reported, which can be done at practically no additional cost.
DOI: 10.12693/APhysPolA.122.601
PACS numbers: 05.70.Ln, 81.30.Kf, 81.70.Pg, 82.60.Fa, 62.20.fg, 87.85.J-