Effect of Cu-substitution on the microstructure and magnetic properties of Fe-15%Ni alloy prepared by mechanical alloying

In this study, nanostructured (Fe85Ni15)100-xCux (x = 0, 0.5, 1.5, 3 and 5) powders were synthesized via mechanical alloying process. The obtained phases, microstructure, and magnetic properties of these alloys were studied by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and vibration sample magnetometer (VSM). XRD results indicated that after a suitable time of milling, Ni and Cu were homogeneously distributed in the Fe matrix, and (bcc) α-(Fe(Ni-Cu)) solid solution was obtained. It was found that by increasing Cu content in the alloy, work hardening increased, and thus the size of grains decreased while the internal micro-strain increased. Also, morphological observations indicated that the addition of Cu led to the formation of finer particles. Also, VSM analysis showed that the addition of Cu into Fe-Ni alloys lowered Ms. On the other hand, the coercivity increased by increasing copper content up to 1.5 at. %.