Abstract:
For the first time, high-resolution differential scanning calorimetry provides information on the enthalpy and entropy of crystallization stages during heating of amorphous metal alloys (AMA) metal-metalloid based on iron and cobalt Fe$_{77}$Ni$_1$Si$_9$B$_{13}$ and Fe$_5$Co$_{58}$Ni$_{10}$Si$_{11}$B$_{16}$. The thermodynamic characteristics of AMA during crystallization and of the basic elements Fe and Co during their crystallization from the melt have been analyzed. In all cases without exception, the enthalpy and entropy values of AMA crystallization are markedly smaller than those of base elements crystallization from the melt. The activation energies of phase transformation during heating of AMA at the first and second stages of their realization have been determined. A marked effect of heating rate (5–40 K/min) on the enthalpy and entropy of crystallization of the Co-based metal-metalloid alloy was found. It is shown that maturation of an iron-based alloy at room temperature for 10 years leads to a noticeable decrease in the exothermic effect of its crystallization while preserving the two-stage character of such transformation.
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