Structural and mossbauer studies of mechanically prepared Fe_(70)Cu_(30) alloy

摘要

A specimen of Fe_(70)Cu_(30) was mechanically alloyed by ball milling for different times the proper amounts of the elements, which are immiscible according to the equilibrium phase diagram. A combination of x-ray diffractometry and Mossbauer spectroscopy has been used to characterize the alloy. X-ray diffraction results indicate an increase in the lattice parameter of both bcc and fcc phases as a function of milling time. The bcc phase subsequently diminishes due to the progressive incorporation of the iron atoms into the fcc copper matrix. Measurements of the width at half-maximum of the peak have confirmed that the average crystallite size decreases with increasing milling time. Room temperature Mossbauer spectroscopy results demonstrate that iron exists in more than one magnetic phase. A broad magnetic component corresponding to the fcc Fe-Cu extended solid solution appeared in Mossbauer spectra of all samples under investigation. Also, the spectra indicate the presence of a paramgnetic component corresponding to square-Fe, which increases in relative intensity with milling time.