Structural properties of FCC and HCP phases in the Fe–Mn–Si system: A neutron diffraction experiment

A neutron diffraction study was carried out on metastable FCC and HCP phases in the Fe–Mn–Si system using small pieces of material inside a rotating device to simulate a polycrystalline randomly oriented sample. The experiments were performed on a set of Fe–Mn–Si alloys (16 at.% ≤ CMn ≤ 32 at.% and 0 at.% ≤ CSi ≤ 12 at.%). FCC and HCP phases were retained at room temperature by a fast quench into water and a subsequent cooling down in liquid nitrogen. The effect of Mn and Si on lattice parameters, average volume per atom and phase fractions were established. The cell parameters for both phases are well described by means of an extrapolation of Vegardʹs law to three alloying elements.