Title of article :
Crystallization Kinetics of Misch Metal Based Bulk Metallic Glasses
Author/Authors :
Xiaofeng Wu ، نويسنده , , Likai Meng، نويسنده , , Wei Zhao، نويسنده , , Zhongyuan Suo، نويسنده , , Yi Si، نويسنده , , Keqiang Qiu، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Abstract :
The crystallization kinetics of Mm55Al25Cu10Ni5Co5 bulk metallic glass (BMG) was investigated by means of differential scanning calorimetry (DSC) in the mode of continuous heating or isothermal annealing. It was found that the apparent activation energy Eg, Ex and Ep of the BMG calculated by Kissingerʹs method were 189.58, 170.68 and 170.41 kJ·mol−1, respectively, which was bigger than those of La55Al25Cu10Ni5Co5 BMG indicating that thermal stability of the former was higher than that of the latter. The local activation energy obtained using Ozawa equation decreased as crystallization proceeded except for the initial stage. The Avrami exponents were calculated to be in the range of 3.26 ∼ 5.23 for different crystallization stages and isothermal temperatures. This implied that crystallization of Mm55 Al25Cu10Ni5Co5 BMG was governed by diffusion-controlled three-dimensional growth with either reduced or increased nucleation rate, depending on isothermal temperature. Inconsistency of thermal stability with glass-forming ability for Mm(La)-Al-Cu-Ni-Co BMGs was discussed.
Keywords :
misch metal , bulk metallic glasses , rare earths , thermal analysis , Crystallization kinetics
Journal title :
Journal of Rare Earths
Journal title :
Journal of Rare Earths