Abstract: A gamma titanium aluminide alloy article, is prepared using a piece of a gamma titanium aluminide alloy having a composition capable of forming alpha, alpha-2, and gamma phases. The alpha transus temperature of the gamma titanium aluminide alloy piece is determined. The gamma titanium aluminide alloy piece is consolidated by hot isostatic pressing at a temperature of from about 50 F. to about 250 F. below the alpha transus temperature and at a pressure of from about 10,000 to about 30,000 pounds per square inch, for a duration of from about 1 to about 20 hours. The piece is heat treated at a temperature of from about 5 F. to about 300 F. below the alpha transus temperature for a time sufficient to refine the microstructure and generate a microstructure comprising from about 10 to about 90 volume percent gamma phase. The step of heat treating is conducted at a temperature of from about 45 F. to about 200 F. above the temperature of the step of hot isostatic pressing.

Abstract: A gamma titanium aluminide alloy article is produced from a piece of cast gamma titanium aluminide alloy by consolidating the gamma titanium aluminide alloy piece at a temperature above the eutectoid to reduce porosity therein, preferably by hot isostatic pressing. The piece is first heat treated at a temperature above the eutectoid for a time sufficient to form a structure of gamma grains plus lamellar colonies of alpha and gamma phases, and thereafter second heat treated at a temperature below the eutectoid to grow gamma grains within the colony structure, thereby reducing the effective grain size of the colony structure. There may follow an additional heat treatment just below the alpha transus to reform any remaining colony structure to produce a structure having isolated alpha-two laths within gamma grains.

Abstract: An as-cast gamma titanium-aluminide alloy, typically having a composition of from about 45.0 to about 48.5 atomic percent aluminum, is pre-HIP heat treated at a temperature of from about 1900.degree. F. to about 2100.degree. F. for a time of from about 50 to about 5 hours. The gamma titanium-aluminide alloy is thereafter hot isostatically pressed at a temperature of about 2200.degree. F. Hot isostatic pressing is preferably followed by a further heat treatment at a temperature of about 1850.degree.-2200.degree. F.

Abstract: A gamma titanium aluminide alloy is provided, based on the intermetallic compound TiAl, in which the resulting alloy is characterized by high creep strength and environmental resistance at elevated temperatures in excess of about 650.degree. C., and as high as about 850.degree. C. The alloy achieves these desirable properties through limited and interrelated additions of chromium, niobium and tantalum, whose combined amount is established by a minimum amount necessary to achieve a desired level of oxidation resistance.

Abstract: A nickel-based superalloy consisting essentially of, in weight percent, from about 4 to about 5 percent chromium, from about 11 to about 14 percent cobalt, from about 4 to about 8 percent tungsten, from about 6 to about 10 percent tantalum, from about 5 to about 7 percent aluminum, from about 5.5 to about 8 percent rhenium, from about 0 to about 0.50 percent hafnium, from about 0 to about 0.07 percent carbon, from 0 to about 0.01 percent boron, from 0 to about 0.030 percent yttrium, from 0 to about 6 percent ruthenium, from 0 to about 1 percent molybdenum, from 0 to about 1 percent niobium, and the balance essentially nickel. Articles made from the superalloy of the invention are especially useful when cast as single crystal airfoils for use in advanced gas turbine engines.

Abstract: A heat treating method for promoting directional recrystallization in objects in general and, more particularly, forgings having relatively low length to thickness ratios. The objects are partially embedded in containers having insulating material therein. The containers are placed into furnaces wherein the rate of the advancing isotherm travelling through the objects are controlled. This process may be used in lieu of zone annealing and static recrystallization heat treatments.