The XAFS and XRD techniques were used to study the local structure changes around Fe and Cu atoms in the mechanical alloying (MA) Fe70Cu30 with the milling times. At the initial MA stage milling for 2 hours, the Cu fcc lattice in Fe70Cu30 mixture is largely distorted, and the disorder factor σ(σ=σT+σS) of Cu atoms is about 0.0190 nm. After being milled for 5 hours, part of the Cu atoms located at the grain boundaries diffuses into the bcc lattice of the α-Fe phase, which makes the average disorder factor σ around Cu atoms decrease to 0.0108 nm. When the milling time reaches 10 hours, most of the Fe atoms are in the fcc Fe-Cu phase whose disorder factor σ is about 0.0119 nm, while the local structures of Cu atoms mainly maintain fcc structure, and the σ around the Cu atoms is about 0.0110 nm. We consider that the bcc structural Fe-Cu phase might be induced into the fcc structure by Cu atoms, when the concentration of Cu atoms incorporated into the bcc Fe-Cu phase is increased to about 30%—40%. The XAFS result of the Fe70Cu30 milled for 20 hours is similar to that of the Fe70Cu30 milled for 10 hours. The final MA product is composed of two phases: Fe80Cu20-like bcc structure and Fe60Cu40-like fcc structure.
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