机械合金化过程中Fe50Als50二元系的结构演变

利用高能球磨和后续热处理技术制备纳米晶Fe5A150（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（A1）固溶体。机械合金化合成Fe（Al）遵循连续扩散混合机制；球磨30h后，粉体主要由纳米晶Fe（A1）构成，晶粒尺寸5．65nm；热处理导致Fe（A1）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。

Structure evolution during mechanical alloying of FesoAlso binary system

Nanocrystalline Fe50Al50(mole fraction,%) alloy powder was synthesized by high-energy ball milling and subsequent heat treating.Both the structural evolution of elemental powder during mechanical alloying and the effect of heat treatment on microstructure of as-milled powder were investigated by X-ray diffractometry(XRD),transmission electron microscopy(TEM) and scanning electron microscopy(SEM).The mechanical alloying mechanism of Fe50Al50 powder during ball milling was also discussed.The results show that the diffusion of Al into Fe lattice occurs during milling,leading to the formation of Fe(Al) solid solution.The process was controlled by continuous diffusion mixing mechanism.After milling for 30 h,the powder is composed of Fe(Al) with grain size of 5.65 nm.The transformation from the disordered Fe(Al) solid solution into the ordered B2-FeAl intermetallic compound occurs after heat treating,accompanying with the growth of B2-FeAl grain which is still in nanometer scale.