采用差示扫描量热分析(DSC)和X射线衍射技术(XRD)研究了非晶态合金Co_(65)Fe_4Ni_2Si_(15)B_(14)的非等温晶化动力学.结果表明,初始晶化的晶化峰值温度T_p与升温速率β呈线性关系:T_p=11.49lnβ+795.43.采用Kissinger和Doyle-Ozawa方法计算了表观晶化激活能E_a,分别为471.68kJ/mol和461.50kJ/mol.进一步研究发现,该非晶合金的晶化为多阶段的连续形核直至饱和的过程;当进入稳定晶化阶段时,剩余非晶的局域晶化激活能逐渐下降,非晶基体的热稳定性降低,这是由B原子的高温扩散导致的.同时,局域Avrami指数n(α)也反映了不同晶化阶段的形核长大机制.
The non-isothermal kinetics of amorphous alloy Co_(65)Fe_4 Ni_2Si_(15)B_(14) is investigated by differential Scanning calorimeter(DSC)and X-ray diffraction(XRD).The results show that there is a linear relationship between the peak temperature T_p(K)and heating rate β:T_p=11.49lnβ+795.43.The apparent crystallization activation energy E_a is calculated to be 471.68kJ/mol and 461.50kJ/mol by Kissinger and Doyle-Ozawa method,respectively.The crystallization of this amorphouS alloy is a multi-stage continuous nucleation up to saturation process.The local erystailization energy decreases gradually indicating that the thermal stability of the residual amorphous matrix becomes weak at the steady crystallization stage,which is ascribed to the diffusion of boron atoms at elevated temperatures.Meanwhile,the local Avrami exponent n(α)exhibits the nucleation and growth mechanism at different crystallization stages.
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