Abstract
The Mossbauer effect has been used in a study of CuFe alloys containing up to 4.6 at% iron over the temperature range 4.2 to 300K. It is found that face centred cubic gamma -Fe is not retained in CuFe alloys quenched sufficiently rapidly from the solid solution region but that the spectra of the solution quenched alloys are consistent with a model in which the iron atoms tend to form clusters. After allowing for the alpha -Fe content in a concentrated alloy a value of 3.1+or-0.2 at% is obtained as the solubility limit for Fe in Cu at 1000 degrees C in agreement with values obtained by other techniques. The precipitation of gamma -Fe and the subsequent development of alpha -Fe has been observed in alloys heat treated at 650 degrees C. At low temperatures gamma -Fe is known to be antiferromagnetic and a value of TN=63+or-4K is obtained for the Neel temperature of gamma -Fe precipitates in copper and a value of 2.7+or-0.3T for the magnetic hyperfine field at 4.2K. By applying an external magnetic field of 8T at 4.2K the magnetic hyperfine spectrum of theta -Fe has been resolved in a composite spectrum.