Non-isothermal crystallization transformation kinetics analysis and isothermal crystallization kinetics in super-cooled liquid region (SLR) of (Ce0.72Cu0.28)90 − xAl10Fex (x = 0, 5 or 10) bulk metallic glasses

Abstract

Crystallization transformation kinetics in the non-isothermal and isothermal modes of (Ce0.72Cu0.28)90−xAl10Fex (x=0, 5 or 10) bulk metallic glasses was studied by differential scanning calorimetry (DSC). In the non-isothermal crystallization mode, the various heating rate (VHR) method and Kissinger–Akahira–Sunose (KAS) method were used to analyze the crystallization kinetics. The results revealed that the features of thermal–physical properties and crystallization kinetics are sensitive to iron content. (Ce0.72Cu0.28)90−xAl10Fex (x=0, 5 or 10) bulk metallic glasses show higher stability against crystallization with Fe content increased. The Johnson–Mehl–Avrami (JMA) model was used to analyze the crystallization kinetics in the non-isothermal and isothermal modes. In isothermal mode, the Avrami exponents n for x=0, 5 or 10 are 1.50, 1.86 and 1.56, respectively, which imply that the minor Fe addition might form a new atomic microstructure. The nucleation rate reaches zero when x=0 during the crystallization process; when x=5 or 10, the nucleation size increases by decreasing nucleation rate during crystallization process. In addition, the incubation time is sensitive to annealing temperatures, and the incubation period of crystallization becomes longer as annealing temperature decreases. Finally, the n values of (Ce0.72Cu0.28)90−xAl10Fex (x=0, 5 or 10) bulk metallic glasses were different in the non-isothermal and isothermal modes, indicating different nucleation and growth behaviors in the crystallization process.