Experimental and theoretical investigations on phase diagram of Fe-base ternary ordering alloys

Phase separations in many ternary ordering Fe-X-Y ( X = Al, Si and Y = Co, V, Ge ) were investigated mainly by means of transmission electron microscopy and thereby the phase diagrams were experimentally obtained. Many modes of phase separation are recognised in these alloys systems and various types of phase diagram are obtained. The free energies of these ordered phases are evaluated by statistical approach employing Bragg-Williams-Gorsky approximation : the magnetic interaction are taken into account between the first and the second nearest neighbours spins of atoms as well as the usual atomic interactions up to the second nearest neighbours. The equilibrium phase diagrams given by the present calculation are almost consistent with the diagrams experimentally obtained