METHOD FOR FABRICATING SHELL MOLDS FOR THE PRODUCTION OF SUPERALLOY CASTINGS

摘要

A method for producing shell molds for the investment casting and subsequent directional solidification of nickel and cobalt based superalloys is described. The shell mold is composed of high purity alumina and characterized by the presence of silica in trace form only. The shell mold of the present invention is nonreactive with molten nickel and cobalt base superalloys even during exposures of up to 12 hours. Additionally the alumina shell mold of the present invention has a unique combination of mechanical strength and stability at elevated temperatures.