NEUTRON DIFFRACTION STUDY ON SITE OCCUPATION OF SUBSTITUTIONAL ELEMENTS AT SUBLATTICE IN Fe_3Al INTERMETALLICS

The site occupation of substitutional elements Cr, Mo, Ti, Ni, Mn, Si at sublattices in DO3 type stoichiometric Fe3Al intermetallics, and effects of the elements on magnetic momentum of unit cell and DO3→B2 transformation behaviour have been determined by means of neutron diffractometry. The experimental results indicate that Cr, Mo and Ti atoms all occupy the next nearest neighbour of Al atom, Ni and Mn atoms the nearest neighbour, while Si atoms occupy the positions of AI atoms. All the alloying elements investigated in the present work decrease order degree of DO3-type Fe3Al alloy, and modify the magnetic momentums of two type Fe atoms in the unit cell.