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用标准单辊甩带技术在大气环境下制备Fe73.5Si13.5-x Gex B9Cu1Nb3(x=3,6)非晶条带,分别在470℃、510℃、550℃和590℃对非晶条带进行真空等温退火1 h后,在非晶基体中形成了纳米晶相。用X射线衍射(XRD),透射电镜(TEM)和差示扫描量热法(DSC)测量研究了快淬态和热处理后样品的结构和结晶动力学。基于差热分析的数据,使用Kissinger,Ozawa和AugisBennett模型计算了非晶条带的结晶激活能,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同的。晶化初期的机理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;晶化中后期为一维形核和生长的表面晶化过程,形核速率近似为零。基于XRD和TEM测量结果,分别在510℃、550℃和590℃真空等温退火1 h后,在Fe73.5Si13.5-x Gex B9Cu1Nb3(x=3,6)非晶条带中析出的α-Fe(Si,Ge)相的平均晶粒尺寸D小于15 nm。
An amorphous strip of Fe73.5Si13.5-x Gex B9Cu1Nb3 (x = 3,6) was prepared at atmospheric temperature by using a standard single-roll rejection technique at 470 ℃, 510 ℃, 550 ℃ and 590 ℃ for amorphous After vacuum annealing for 1 h, a nanocrystalline phase was formed in the amorphous matrix. The structure and crystallization kinetics of samples after quenching and heat treatment were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Based on the data of differential thermal analysis, the crystallization activation energy of amorphous ribbons was calculated using Kissinger, Ozawa and Augis Bennett models. The local Avrami factor n of amorphous ribbon initial crystallization was calculated by the Johnson-Mehl-Avrami (JMA) equation. The significant change of the local Avrami factor n with the crystallization volume fraction α indicates that the mechanism of the non-isothermal initial crystallization of amorphous ribbons is different at different crystallization stages. The mechanism of the initial crystallization is the diffusion-controlled three-dimensional nucleation and grain growth of the overall crystallization, nucleation rate gradually reduced; the crystallization of the late one-dimensional nucleation and growth of the surface crystallization process, the nucleation rate is approximately zero. Based on the results of XRD and TEM measurements, the α-Si precipitated in the Fe73.5Si13.5-xGexB9Cu1Nb3 (x = 3,6) amorphous alloy was annealed at 510 ℃, 550 ℃ and 590 ℃ for 1 h, respectively. The average grain size D of the Fe (Si, Ge) phase is less than 15 nm.