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The crystallization transformation kinetics of Ti20Zr20Hf20Be20(Cu50Ni50)20 high-entropy bulk metallic glass under non-isothermal conditions are investigated using differential scanning calorimetry. The alloy shows two distinct crystallization events. The activation energies of the crystallization events are determined using Kissinger, Ozawa and Augis-Bennett methodologies. Further, we observe that similar values are obtained using the three equations. The activation energy of the initial crystallization event is observed to be slightly small as compared to that of the second event. This implies that the initial crystallization event may have been easier to be occurred. The local activation energy (E(x)) maximizes in the initial stage of crystallization and keeps dropping in subsequent crystallization process. The non-isothermal crystallization kinetics are further analyzed using the modified Johnson-Mehl-Avrami (JMA) equation. Further, the Avrami exponent values are observed to be 1.5 < n(x) < 2.5 for approximately the entire period of the initial crystallization event and for most instances (0.1 < x < 0.6) of the second crystallization event, which implies that the mechanism of crystallization is significantly controlled by diffusion-controlled two- and three-dimensional growth along with a decreasing nucleation rate. [ABSTRACT FROM AUTHOR]

• Investigated the crystallization kinetics of Hf 28 Be 18 Ti 17 Zr 17 Cu 7.5 Ni 12.5 HE-BMG. • Three crystallization reactions were characterized. • Analysis of non-isothermal crystallization kinetics by SB model. • Isothermal crystallization kinetics were studied by the JMA model. Crystallization kinetics of Hf 28 Be 18 Ti 17 Zr 17 Cu 7.5 Ni 12.5 high-entropy bulk metallic glass (HE-BMG) in the non-isothermal and isothermal conditions were investigated by differential scanning calorimetry (DSC). In non-isothermal crystallization condition, DSC traces exhibited three crystallization processes. The apparent activation energies of peak crystallization temperatures were calculated by Kissinger methods and found to be E p1 > E p2 > E p3. The dependence of local activation energy on crystallized volume fraction was summarized by the Kissinger-Akahira-Sunose (KAS) method. The non-isothermal crystallization reaction was described mathematically using the Šesták-Berggren model. In the isothermal crystallization condition, with the increase of annealing temperature, the incubation time and crystallization time become shorter and the crystallization peak becomes higher. All Avrami indices were less than 2.5, indicating that crystallization of glassy alloy is dominated by a diffusion-controlled three-dimensional growth with a decreasing nucleation rate. [ABSTRACT FROM AUTHOR]