摘要
利用XAFS和XRD方法分别研究了机械合金化 80h制备的Fe10 0 -xCux系统的晶体结构及Fe和Cu原子的局域配位环境 .结果表明 ,当x>4 0时 ,样品中Fe原子的bcc结构消失 ,Cu原子的近邻结构基本不变 ,fcc晶格参数随x的增加而减小 ;当x <30时 ,Cu原子的fcc结构消失 ,Fe原子的近邻结构基本不变 ,bcc晶格参数随Cu原子的比例减小而增大 ;而x=30左右时 ,fcc和bcc结构共存 .研究结果还表明 ,Fe原子和Cu原子的比例不是相差很大时 ,Fe原子和Cu原子的近邻配位无序度会在很大的范围内变化 ,说明Fe -Cu二元体系不可能形成均匀的过饱和固溶体 ,存在Cu富集区和Fe富集区 。
The structures of the mechanically alloyed Fe 100- x Cu x ( x =0,20,30,40,60,70,100) after milling for 80 hours were investigated by X-ray absorption fine structure (XAFS) and X-ray diffraction (XRD).When the weight ratio of the balls to the powder was 40:1,for the Fe 100- x Cu x ( x ≥40) alloys,the XRD results show that diffraction peaks of α-Fe disapeared,and only the diffraction peaks with fcc-like structure were observed.The fcc-like lattice parameter increases with Fe concentration.On the contrary,for the Fe 100- x Cu x ( x <30) alloys,only the diffraction peaks with bcc-like structure were observed.The bcc-like lattice parameter decreases with Cu concentration.The XAFS results show that the local structure evolution of Fe atoms was different from that of Cu atoms.The local structures around Fe atoms had been greatly changed and its disorder evidently increased,but the Cu atoms maintain the original structure geometry.So,mechanically alloyed Fe 100- x Cu x is not a homogeneous supersaturated solid solution and consists of Fe-rich and Cu-rich regions.
出处
《吉首大学学报（自然科学版）》
CAS
2002年第1期8-12,共5页
Journal of Jishou University(Natural Sciences Edition)
基金
国家自然科学基金资助项目 (196 0 4 0 11)
中国科学院"百人计划"资助项目
