DISSOLUTION OF IRON TO COPPER IN Fe₆₀Cu₄₀ ALLOY BY MECHANICAL ALLOYING AND SUBSEQUENT DECOMPOSITION

A metastable alloy with composition Fe₆₀Cu₄₀ can be prepared in single phase of a fcc structure by mechanical alloying, although Fe-Cu system is virtually immiscible in its equilibrium state at ambient temperature. The M\ddot\rm ossbauer spectra of this supersaturated solid solution could be fitted by two subspectra whose hyperfine magnetic fields are 200 kOe and 250kOe. In this metastable alloy, the iron atoms at the interface are easy to form clusters characterized as \alpha-Fe at a temperature below 250℃, whereas the iron atoms in the body will cluster together at a higher temperature above 350℃ and behave as \gamma-Fe, and then transform to ferromagnetic bcc iron occurs.