Crystal structure and morphology of the alloys for cast permanent magnets

The structure of the Ticonal-type alloys was investigated using a transmission electron microscope technique. Two-dimensional square macrolattice was observed in the section normal to the magnetic field which was applied at heat treatment. The translation vectors of that lattice coincide with the directions of the crystal lattice. There were equiaxed regions of various contrasts at the corners and center of the unit cell and flat intermediate layers on the sides. Thus the two-phase model of the structure is only an approximation. The prolonged tempering at high temperature (800°C, 20 hours) of specimens after they are subjected to the thermal magnetic treatment gives rise to the development of the complex modulated structure.