The objective of the study was to quantify changes in the phase transformation behavior in NiTi SMA wires when they are heat treated and thermally cycled at zero stress. The analysis involved weight fraction evolution derived from XRD profiles using the Rietveld method and specific software. The results were compared with those obtained from ER measurements. The study then analyzed how both treatments affect the SMA hardness. The results show how R-phase presence decreases with the increase in heat treatment temperature and indicate that the R-phase is developed or stabilized by thermal cycling depending on the heat treatment temperature. The SMA hardness increases due to thermal cycling. The increase is greater if there has been no R-phase development during the heat treatment. Combining the results of these techniques is deemed to be the most suitable combination of heat treatment and thermal cycling by which to improve the SMA’s functional properties.

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