The response of cobalt-free Udimet 700 type alloy to modified heat treatments

A superalloy based on Udimet 700, in which all of the cobalt had been replaced by nickel, was prepared from hot isostatically pressed pre-alloyed powders. This material was given various heat treatments consisting of partial solutioning and ageing in a sequence of four different temperatures. Comparisons were made of microstructures and mechanical properties. Best results were obtained by partially solutioning at 1145° C and ageing through a sequence of 870, 1030, 650, and 760° C. This heat treatment also provided significantly improved properties for wrought material of the same composition. The results suggest that cobalt free Udimet 700 should be considered as a substitute for Udimet 700 with the standard 17wt% cobalt content.