Solids

Features of polymorphic transformation during heating and cooling of cobalt

L. V. Spivak^a, N. E. Shchepina<sup>b

a</sup> Perm State National Research University, Perm, Russia
^b Natural Sciences Institute, Perm University, Perm, Russia

Abstract: Differential scanning calorimetry was used to study the regularities of polymorphic $\alpha\leftrightarrow\beta$-transformation in polycrystalline cobalt. The value of the activation energy of the $\alpha\to\beta$-transformation during heating of cobalt (290–50 kJ/mol), enthalpy and entropy, depending on the thermal history of the metal, is determined. It is shown that the mechanisms of recrystallization under heating are closer to the first-order I phase transformations. When cooling under conditions of limited diffusion mobility of cobalt atoms, recrystallization is apparently carried out due to the passage of several diffusion-free mechanisms of phase transformation, implemented in close temperature ranges.

Keywords: activation energy, cobalt, calorimetry, polymorphism, enthalpy, entropy.

Received: 20.11.2021
Revised: 03.01.2022
Accepted: 24.01.2022

DOI: 10.21883/JTF.2022.04.52244.295-21

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