Structures and mechanical properties of an FeCo-2V alloy

Abstract

Effect of structural changes based on heat treatments upon the ductility of an FeCo-2V alloy has been studied. The ductility does not always result from the martensitic transformation, but it always results from the ferritic structure which is composed of large and heterogeneous grains, whenever the specimens are quenched from a temperature of the ferritic region. In the case of the specimens heat treated at and quenched from a temperature where two phases can coexist, the ductility is strongly affected by the uniformity of the mixed structure obtained by such a treatment. The ductility of the mixed structure is improved by combinations of various heat treatments. After ordering, however, all specimens treated have never shown any ductility. The distribution of the precipitates occurring during ordering have shown a remarked difference between as-cast and as-cold-rolled specimen; the former is dilute, while the latter is dense. The composition of the individual particles extracted from the samples which are satisfactorily aged are shown to be about 64Co-21V-15Fe on average. Following to the information, a possible mechanism of improving the ductility of the alloys is argued on a model of local concentration-disordered zones.