Effects of heat-flux features on the differential scanning calorimetry curve of a thermoelastic martensitic transformation

The characterization of the heat effect of thermoelastic martensitic transformation is usually carried out in a heat-flux differential scanning calorimetry (DSC) device. The temperature of the sample during a DSC cycle differs from the temperature of the reference. This means that the measured heat flow covers both the latent heat and the heat quantity needing to heat up (cool down) the sample. The later heat quantity is the temperature balancing between the sample and the reference. Furthermore, the temperature balancing is still measured when the transformation is finished. According to this, using the peak endpoint to determine the transformation (austenite or martensite) finish temperature gives an error, which depends on the deviceʹs time constant. The temperature balancing is sensitive on the rate of heating (and cooling) and the mass of the sample. When evaluating DSC curves of heat-flux DSC, one must take into account these facts not to get false results. Cu–Al–Ni single crystal was examined to show the above-mentioned phenomena, and an evaluation program was developed to improve the quantitative analyzing of DSC peaks.