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利用标准的单辊甩带技术在大气环境下制备了Fe73.5-xCoxSi13.5B9Cu1Nb3(x=10、30、50)非晶条带。在550和600℃下分别对非晶条带进行真空等温退火1h,从而在非晶基体中形成纳米晶相。X射线衍射(XRD)分析结果表明,550和600℃真空等温退火1h后,Fe73.5-xCoxSi13.5B9Cu1Nb3(x=10、30、50)非晶条带中析出的α-Fe(Co、Si)相的平均晶粒尺寸D分别为19.3、20.1、22.8nm和24.8、25.2、26.5nm。基于差热分析的数据,利用Kissinger、Ozawa和Augis-Bennett模型计算了非晶条带的初始结晶激活能,利用Johnson-Mehl-Avrami(JMA)方程计算了非晶条带初始结晶的局域Avrami因子n,局域Avrami因子n随晶化体积分数α的显著变化说明非晶条带非等温初始结晶的机理在不同的晶化阶段是不一样的,晶化初期(0<α<0.2)是扩散控制的三维形核和晶粒生长的整体晶化,形核速率逐渐减小;晶化中后期(0.2<α<1.0)为一维形核和生长的表面晶化过程,形核速率近似为零。
Fe73.5-xCoxSi13.5B9Cu1Nb3 (x = 10, 30, 50) amorphous ribbons were prepared in the atmosphere using a standard single roll rejection technique. The amorphous strip was annealed in vacuum at 550 and 600 ℃ for 1h, respectively, to form a nanocrystalline phase in the amorphous matrix. The results of X-ray diffraction (XRD) analysis showed that α-Fe (Co, Si) precipitated in amorphous Fe73.5-xCoxSi13.5B9Cu1Nb3 (x = 10, 30, ) The average grain sizes D of the phases were 19.3, 20.1, 22.8 nm and 24.8, 25.2, 26.5 nm, respectively. Based on the data of differential thermal analysis, the initial crystallization activation energy of the amorphous zone was calculated by Kissinger, Ozawa and Augis-Bennett models. The local Avrami of amorphous zone was calculated by the Johnson-Mehl-Avrami (JMA) equation Factor n, the significant change of local Avrami factor n with the volume fraction α of crystallization indicates that the mechanism of non-isothermal initial crystallization of amorphous ribbons is different at different crystallization stages. The initial crystallization (0 <α <0.2) is Diffusion-controlled three-dimensional nucleation and grain growth of the overall crystallization, nucleation rate gradually reduced; the late crystallization (0.2 <α <1.0) for the one-dimensional nucleation and growth of the surface crystallization process, the nucleation rate is similar to Zero.