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利用高能球磨和后续热处理技术制备纳米晶Fe50Al50(摩尔分数,%)合金粉体。采用X射线衍射、透射电镜和扫描电镜对元素混合粉在机械合金化过程中的结构演变及热处理对合金化粉体结构的影响等进行分析,讨论其机械合金化合成机制。结果表明:球磨过程中Al向Fe中扩散,形成Fe(Al)固溶体。机械合金化合成Fe(Al)遵循连续扩散混合机制;球磨30 h后,粉体主要由纳米晶Fe(Al)构成,晶粒尺寸5.65 nm;热处理导致Fe(Al)纳米晶粉体有序度提高,转变为有序的B2型FeAl金属间化合物,粉体的晶粒尺寸增大,但仍在纳米尺度范围。
Nanocrystalline Fe50Al50 (mole fraction,%) alloy powders were prepared by high energy ball milling and subsequent heat treatment. X-ray diffraction, transmission electron microscopy and scanning electron microscopy were used to analyze the structural evolution of the elemental mixed powder during mechanical alloying and the effect of heat treatment on the structure of the alloying powder. The mechanism of mechanical alloying was discussed. The results show that Al diffuses into Fe during ball milling to form Fe (Al) solid solution. The mechanical alloying synthesis of Fe (Al) followed a continuous diffusion mixing mechanism. After milling for 30 h, the powders were mainly composed of nanocrystalline Fe (Al) with a grain size of 5.65 nm. The thermal treatment led to the ordered degree of Fe (Al) nanocrystalline powders Improve, and transform into an ordered type B2 FeAl intermetallic compound. The grain size of the powder increases, but it is still in the nanoscale range.