Effects of boron addition on a melt-spun Ni-base superalloy

Melt spinning of a nickel-base superalloy containing various amounts of boron up to 3.0 wt% has been carried out to explore the potential of extended boride alloyability through rapid solidification. More specifically, the melt-spinning castability, ribbon-solidification microstructure and heat-treatment precipitation were studied as a function of boron concentration by using analytical electron microscopy and a number of other techniques. Special attention was given to the boride structure, chemistry and thermal stability. The microstructural observations were then correlated to the ribbon bend ductility tested in as-cast and annealed conditions. On the basis of the present results, future investigation of superalloys using the rapid solidification process and the boride alloying concept is discussed.