Study of nanocrystalline FeSi alloys prepared by mechanical alloying

In this work, the refinement of the Fe94Si6 alloy is achieved by mechanical alloying in a high-energy planetary ball mill under argon atmosphere during various milling times up to 10 h. Samples at different milling times were characterized by scanning electron microscope, X-ray diffraction and Mössbauer spectra. After 1 h of milling time, it is observed the refinement and coexistence of two phases: the disordered solid solution of type A2 (α-Fe(Si)) and the ordered solid solution of type B2. The relative concentration of the phase B2 varies with milling time, due to the order–disorder transition. The grain size of the phase A2 decreased most gradually up to 10 nm with increased milling time. Mössbauer spectra show the presence of a ferromagnetic phase with a mean hyperfine field of 30.1 T and a paramagnetic phase with a relative concentration of 6, 5%.