Kinetics of the glass-transition and crystallization process of Fe72−xNbxAl5Ga2P11C6B4 (x=0, 2) metallic glasses

The kinetics of the glass-transition and the crystallization process of multicomponent ferromagnetic Fe72−xNbxAl5Ga2P11C6B4 (x=0, 2) metallic glasses have been investigated by constant-rate heating differential scanning calorimetry at different heating rates. The glass-transition temperature Tg and the crystallization peak temperature Tp shift to higher temperatures with increasing heating rate. The apparent activation energy and the frequency factor are evaluated by the Kissinger method, and the rate constant of the crystallization process is estimated by an Arrhenius law. The kinetics of the glass-transition process have been analyzed in terms of a Vogel–Fulcher–Tammann equation describing the heating rate dependence of the glass-transition temperature. The effect of the niobium addition on the glass-forming ability has been investigated with respect to the glass-transition and crystallization kinetics, revealing that substitution of Nb for Fe does not improve the glass-forming ability and it lowers the thermal stability of the material.