Production of Al-Co-Ni ternary alloys by the SHS method for use in nickel based superalloys manufacturing

Abstract

In this study, Al-Co-Ni ternary alloys were synthesized, in order to obtain low-cost starting material for Ni-based superalloy production, by a self-propagating high temperature synthesis (SHS) both under normal gravity conditions (a=9.81 m/s2) and under high gravity conditions (up to 1000 g-force) by using a centrifugal machine. The mixture of Co3O4-NiO powder were reduced by Al powder for the production of SHS alloys with the estimated compositions of 5-10 mass% Al, 20-65 mass% Co, 25-75 mass% Ni. The effect of green mixture compositions and centrifugal overload on combustion temperature, alloy/slag separations, chemical composition and microstructure of final alloys were investigated. The chemical analysis results showed that production of SHS alloys were achieved by having up to 86.12% of Co and 92.32% of Ni recoveries. The highest metal recovery value was obtained in SHS alloy with the estimated composition of 10%Al-65%Co-25%Ni by the addition of 20% Al2O3 into the green mixture. The metal/slag separation efficiency increased by increasing the centrifugal overload.