A kinetic study of the low temperature decomposition of mechanically alloyed W–Ni–Fe noncrystalline materials

A three-stage crystallization process takes place in W–Ni–Fe noncrystalline alloys fabricated by mechanical alloying (MA). Differential scanning calorimetry (DSC) and isothermal transformation studies were employed to investigate the lowest-temperature decomposition reaction. Results show that this reaction can be described by a first order JMAK (Johnson–Mehl–Avrami–Kolmogorov) equation. As a consequence, the activation energies of the decomposition determined by isothermal transformation studies and DSC (using the Kissinger method) are approximately the same. The activation energy increases with the W content in the glassy phase preceding the transformation.