Abstract: An electrolyte useful in the electrochemical machining of the high strength nickel base superalloys is described. The electrolyte is an aqueous solution containing nitric acid, hydrochloric acid and citric acid in specific quantities. Nickel base superalloys electrochemically machined using the electrolyte of the invention possess extremely smooth machined surfaces which are free from smut and other undesirable surface problems.

Abstract: This invention concerns composite articles, particularly those which contain single crystal components. A method is disclosed for joining single crystals together so that the resultant article is free from high angle grain boundaries and therefore possesses exceptional mechanical properties.

Abstract: The constitutionally complex alloys, particularly those exhibiting good high temperature strength and prone to the development of unacceptable heterogeneity in conventional casting operations, are produced by consolidation of a cold-worked particulate material which is sized to preclude the development thereon, in the time span at temperature used in consolidation, of undesirable surface phases such as carbides which inhibit particulate bonding.

Abstract: 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.

Abstract: A cobalt base superalloy is disclosed which has good elevated temperature properties combined with low density and low cost. The alloy has a nominal composition of .9% carbon, 25% chromium, 15% nickel, 7.5% tungsten, 2.2% titanium, 1.2% zirconium, 1.0% iron, balance essentially cobalt, and is substantially free from columbium and tantalum.