Experimental Investigation of Phase Equilibria in the Co-Cr-Nb System at 1000,1100, and 1200 °C

摘要

Phase equilibria in the Co-Cr-Nb ternary system were experimentally investigated by using back-scattered scanning electron microscopy, electron probe microanalysis, composition mapping and x-ray diffraction on equilibrated aUoys. In this study, isothermal sections of the Co-Cr-Nb ternary system at 1000, 1100 and 1200 °C were determined. The intermetallic compounds Co_7Nb_6 and CoCrNb, together with their single phase regions were determined on all three isotherms, as well as three tie triangles involving the (Nb) + Co_7Nb_6 + CoCrNb, (αCr) +σ+ CoCrNb and (αCo) +σ+ CoCrNb phases. The current diagrams differed significantly from a previous isotherm reported at 1000 °C. The newly determined phase equilibria in the Co-Cr-Nb system may provide useful information for perpendicular magnetic recording materials and high-temperature alloys.