Structure and properties of nanocrystalline Cu70Fe18Co12 obtained by mechanical alloying

Cu70Fe18Co12 alloy is prepared by mechanical alloying of pure Cu, Fe, Co powder using a high energy ball mill, with increasing milling time ranging from 4 to 8, 24, 36 and 54 h. The variation of the morphology and the elemental distribution were measured at these different stages on various grains of the alloy using a scanning electron microscope with a dispersive energy analyzer. Atomic clusters of iron were observed on some grains after 8 h of milling, confirming the non-homogenisation of the powder at this stage. Beyond 12 h, the homogenisation is ensured over a volume of one cube micron. Microstructural changes during the mechanical alloying have been studied by X-ray diffractometry (XRD) and Mössbauer spectroscopy. X-ray diffraction measurements confirm the dissolution of iron and cobalt phases in the FCC matrix of copper after 24 h of milling with increase of the structural parameter. This same dissolution was also measured by Mössbauer spectroscopy, confirming that after 4 h of milling the CuFe phase begins to form and iron dissolution is incomplete with partial amount of alpha Fe phase surviving after 36 h of milling.