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 mul ticomponent ferromagnetic Fe72-xNbxAl5Ga2P11C6B4 (x=0, 2) metallic glasses have been investigated by constant-rate heating differential scanning calor imetry at different heating rates. The glass-transition temperature T-g and the crystallization peak temperature T-p 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 t he glass-transition process have been analyzed in terms of a Vogel-Fulcher- Tammann equation describing the heating rate dependence of the glass-transi tion temperature. The effect of the niobium addition on the glass-forming a bility has been investigated with respect to the glass-transition and cryst allization kinetics, revealing that substitution of Nb for Fe does not impr ove the glass-forming ability and it lowers the thermal stability of the ma terial. (C) 2001 American Institute of Physics.