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利用 XRD和 XAFS方法研究了机械合金化 80 h制备的 Fe10 0 -x Cux 系统 (x=0 ,2 0 ,3 0 ,40 ,6 0 ,70 ,1 0 0 ,x为原子百分比 )的晶体结构和 Fe、Cu原子的局域配位环境。结果表明 ,对于高 Cu原子浓度的 Fe10 0 -xCux(x≥ 40 )样品 ,Fe和 Cu原子的配位环境为 fcc结构 ,对于低 Cu原子浓度的 Fe10 0 -x Cux(x≤ 2 0 )样品 ,Fe和Cu原子的配位环境为 bcc结构。而 x=3 0左右时 ,fcc和 bcc两相结构共存 ,但有较大的晶格扭曲和局域结构形变。XRD和 XAFS结果还表明 ,只有当 x≤ 2 0时 ,机械合金化的 Fe10 0 -x Cux 系统才能形成较为均匀的合金。否则 ,近邻配位无序度会在很大的范围内变化 ,存在 Cu富集区和 Fe富集区 ,并不是均匀的过饱和固溶体
The crystal structure of Fe10 0-x Cux system (x = 0, 20, 30, 40, 60, 70, 100, x is atomic percentage) prepared by mechanical alloying for 80 h was investigated by XRD and XAFS. And Fe, Cu atoms local coordination environment. The results show that for the Fe10 0-xCux (x≥40) samples with high Cu atom concentration, the coordination environment of Fe and Cu atoms is fcc structure. For Fe10 0-x Cux (x≤20) samples with low Cu atom concentration The coordination environment of Fe and Cu atoms is bcc structure. However, when x = 30, the two-phase structure of fcc and bcc coexist, but there is a large lattice distortion and local structure deformation. The XRD and XAFS results also show that the mechanically alloying Fe10 0-x Cux system can form a more homogeneous alloy only when x ≤ 20. Otherwise, the adjacent coordination disorder degree will change in a large range, there is Cu enrichment zone and Fe enrichment zone, not uniform supersaturated solid solution