Investigation of the ternary phase diagram of mechanically alloyed FeCuAg

The structural and magnetic properties of mechanically alloyed Fe-Cu-Ag at room temperature have been investigated using Fe-57 Mossbauer spectroscopy, x-ray diffraction and differential scanning calorimetry. The elements are naturally immiscible, but through prolonged and energetic ball milling (70 hours at 600 rpm) one can make metastable alloys, the structure of which depends on the elemental composition. In the binary Cu-Ag and Fe-Cu systems, crystalline single-phase solid solutions result, whereas in Fe-Ag the alloying is limited, with the product a mixture of elemental particles. In the ternary system it is possible to produce copper- and silver-rich single-phase fee alloys, but not the equivalent bcc iron-based structure. As the proportions of the three elements become more equal, the resulting structure becomes highly disordered or amorphous. The composition range of this amorphous phase is different to that observed in sputtered Fe-Cu-Ag systems.