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通过高能球磨技术制备了Fe-25.68%Dy_2O_3(质量分数)纳米晶混合粉末。采用X射线衍射、扫描电镜和透射电镜对不同球磨时间的混合粉末的组织结构、晶粒大小、微观形貌以及颗粒中化学成分分布情况进行了观察和研究。实验结果表明:混合粉末经过球磨后形成了纳米晶,其组织非常均匀。球磨对Dy_2O_3组元的作用效果明显大于对Fe组元的作用效果。Fe相的衍射峰随球磨时间的增加逐渐宽化,而Dy_2O_3相衍射峰强度逐渐降低,在球磨48 h后几乎消失。结果表明随球磨时间的增加,晶粒尺寸逐渐减小,球磨初期减小很快,球磨后期减小缓慢,最后趋于一个稳定值,48 h后晶粒的平均尺寸约为20 nm。本文同时研究了纳米晶混合体形成和Dy_2O_3相固溶的原因以及微观组织演变的机制。
Fe-25.68% Dy 2 O 3 (mass fraction) nanocrystalline powders were prepared by high-energy ball milling. X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microstructure, grain size, micromorphology and the distribution of chemical components in the powders. The experimental results show that the nanocrystalline is formed by ball milling of the mixed powder and the microstructure is very uniform. The effect of ball milling on Dy 2 O 3 component is obviously greater than that of Fe component. The diffraction peak of Fe phase gradually broadened with the increase of milling time, while the diffraction peak intensity of Dy 2 O 3 phase decreased gradually and almost disappeared after 48 h milling. The results show that with the increase of ball milling time, the grain size decreases gradually, the initial ball milling decreases rapidly and the ball milling decreases slowly, finally reaches a stable value. After 48 h, the average grain size is about 20 nm. In this paper, the reasons for the formation of nanocrystalline hybrids and the solution of Dy 2 O 3 phase and the mechanism of microstructure evolution were also studied.