The face-centred cubic solid solutions in transition metal alloys of the first long period

Abstract

The limits of composition of the face-centred cubic solid solutions in binary alloys of the elements V, Cr, Fe, Co and Ni are discussed. The term group number (G.N.) is used to denote the position of the transition metal in the First Long Period (is. G.N.=4 for Ti). It is shown that if the binary equilibrium diagrams ere drawn in terms of the average G.N. values of the alloy, and if manganese is omitted as an abnormal element, the face-centred cubic solid solutions are stable from G.N. 10 (pure Ni) to a value of about 7.7, in cases where the aim-factors are favourable. The limits of the face-centred cubic solid solution occurs at an approximately constant G.N. value, in very much the same way that the limits of the α-solid solutions in copper and silver alloys occur at an approximately constant electron: atom ratio. It is ah shown that, when plotted in terms of average G.N. value, the liquidus and solidus curves for the γ-phases in the systems Fe-Co and Fe-Ni am almost superposed, this behaviour being analogous to that shown by the α-liquidus and solidua curves in the systems Cu[sbnd]Zn end Cu[sbnd]Ga.