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The data on calorimetric effects during str uctural phase transformations in iron.carbon alloys (steels) are presented. The absence of correlation with the temperatures of points А3 (Am) and the temperatures of recording calorimetric effects during thermal cycling of steels in the intercritical temperature range is shown. Приведены данные по калориметрическим эффектам при структурнофазовых превращениях в железоуглеродистых сплавах (сталях). Показано отсутствие корреляции с температурами точек А3 (Аm) и температурами регистрации калориметрических эффектов при термоциклировании сталей в межкритическом интервале температур.

Based on the analysis of differential scanning calorimetry data, the possibility of classifying the observed endothermic or exothermic transformations as phase transformations of the first oder is considered. Two approaches have been implemented. The first is based on the correspondence between the temperatures of the maximum conversion rate and the temperatures of the extrema on the second derivative of the differential scanning calorimetry signal with respect to temperature. In the second approach, the phase transformation is considered as a kind of kinetic reaction of a chemical process with the determination of some parameters included in the kinetic equations. In this case, the order parameter of such reaction n is obtained from the analysis of the differential scanning calorimetry signal shape in the region of phase transformation registration temperatures. Using the example of experiments carried out during thermal cycling of titanium iodide samples, it is shown that both the first and second approaches make it possible to fairly adequately attribute the processes that cause calorimetric effects on the dependences of differential scanning calorimetry to first-order phase transitions. In particular, the obtained results of differential scanning calorimetry during heating and cooling of iodide titanium show that polymorphic transformations in it are realized by various mechanisms depending on the rate of thermal cycling and the thermal history of the metal. Keywords: activation energy, titanium, calorimetry, polymorphism, structure, approximation.

Differential scanning calorimetry was used to study the Co-C nanocomposite, which is an array of ultrathin carbon nanocages encapsulated cobalt nanoparticles. The activation energy of the α-> β transformation of the nanocomposite and the value of its endothermic effect have been estimated. Thermal effect is much greater than those values that correspond to the observation conditions for α->β transformations in massive cobalt samples. The idea was put forward that transitional transformation is assumed by a non-diffusion, massive mechanism. Keywords: phase transitions, carbon nanocages, cobalt, activation energy.