Abstract: The structures of the mechanically alloyed Fe_100-xCu_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-xCu_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-xCu_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-xCu_x  is not a homogeneous supersaturated solid solution and consists of Fe-rich and Cu-rich regions.

Key words: X-ray absorption fine structure, X-ray diffraction, mechanical alloying