Heat treatment influence on the structural and magnetic properties of the intermetallic Fe_(56.25)Al_(43.75) alloy prepared by mechanical alloying and arc-melted

摘要

Alloys of the Fe_(56.25)Al_(43.75) system were prepared by mechanical alloying (MA) using a high energy planetary ball mill, with milling times in the range from 12 up to 96 h named MA0 samples. The sample milled for 48 hours was heat treated at 700 °C for 9 days. Then this sample was milled for times of 1, 4, 8, 12, 24, and 48 h, named MA1 samples. Additionally, and for comparison, it was prepared a Fe_(56.25)Al_(43.75) sample by arc-melting method. For all samples, the structural and magnetic study was conducted by X-rays diffraction (XRD) and M?ssbauer spectrometry (MS). The XRD results show that the system is nanostructured and the MA0 samples present only the BCC disordered phase, whose lattice parameter remains relatively constant with milling time. For MA1 samples it was identify the FeAl, Fe_3Al, FeO and α-Fe phases. The M?ssbauer spectra for all samples were fitted by using a hyperfine magnetic field distribution (HMFD), and a paramagnetic site for all the times used here. The ferromagnetism increases when milling time increases, and this is a consequence of the structural disorder induced by mechanical alloying.