Magyar Tudományos Akadémia
Crystallization kinetics of metallic glasses
The characterization of the crystallization kinetics of amorphous soft magnetic alloys will be presented. The crystallization is accompanied by changes of many properties such as density, the electrical resistivity, magnetic properties, the heat capacity. It occurs by a nucleation and growth processes identical to that in liquids just below the melting point, however, the modes of crystallization from the metastable amorphous state to the stable crystalline state depend on various parameters, such as the composition, the concentration of nucleation sites, the activation energy, the thermal history of the sample and annealing procedures. The alternating current thermomagnetometry (TMAG) and differential scanning calorimetry (DSC) have been used to observe crystallization kinetics of Fe85-xCrxB15 alloys and some bulk amorphous materials. Kissinger method was used to determine activation energy of the phase transformation by measure of the DSC peak temperature shift induced by variation of the heating rate. The DSC results are compared with corresponding thermomagnetic effects observed by TMAG.
2005. május 24. (kedd) de. 10:00
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