Abstract: A tantalum-containing nickel base superalloy having a .gamma.' phase has greatly improved maximum tensile strength which is substantially independent of the frequency of the stress is processed by forging above the .gamma.' solvus temperature and annealing above the recrystallization temperature of the alloy.

Abstract: A nickel based superalloy composition is disclosed that provides increased high temperature stress-rupture strength and improved resistance to fatigue crack propagation at elevated temperatures up to about 760.degree. C. The composition is comprised of, by weight percent, about 10% to 12% chromium, about 17% to 19% cobalt, about 1.5% to 3.5% molybdenum, about 4.5% to 6.5% tungsten, about 3.25% to 4.25% aluminum, about 3.25% to 4.25% titanium, about 2.5% to 3,5% tantalum, about 0.02% to 0.08% zirconium, about 0.005% to 0.03% boron, less than 0.1% carbon, and the balance essentially nickel. Thermomechanical processing including isothermal forging at controlled strain rates and temperature ranges, supersolvus annealing, and slow cooling are disclosed for producing an enlarged grain structure that provides the improved properties in the alloy of this invention.

Abstract: A dual alloy disk made from a rim alloy having high stress rupture and creep resistance as well as good hold time fatigue crack resistance and a hub alloy having high tensile strength and good low cycle fatigue crack resistance is described. The dual alloy disk is designed for use as a disk in gas turbine engines operating as high as 1500.degree. F. The hub and rim are joined together at a substantially defect-free joint to form a turbine disk having improved properties in both the hub and rim regions.

Abstract: A method of improving the low temperature ductility of an iron-aluminide is taught. The aluminide for which the method is applicable is one having between 30 and 50 atom percent of aluminum. The aluminide may also have substituents for part of the iron and for the aluminum. The alloy may contain up to 10 atom percent of substituents for the iron selected from the group of metals comprising nickel cobalt chromium and manganese. The alloy may also contain substituents for the aluminum of up to 5 atom percent of a metal selected from the group comprising titanium, niobium, tantalum, hafnium, zirconium, vanadium, and silicon. The alloy has a B2 crystal structure. The first step of the process is to select the metal to be processed. The next step is to directionally solidify the selected metal. The next step is to determine the Ductile Brittle Transition Temperature (DBTT). The metal is then heated to above the DBTT and is deformed while above the DBTT temperature.

Abstract: Improved, creep-stress rupture and hold-time fatigue resistant nickel base alloys for use at elevated temperatures are disclosed. The alloys consists essentially of, in weight percent, 10.9 to 12.9% Co; 11.8 to 13.8% Cr; 4.6 to 5.6% Mo; 2.1 to 3.1% Al; 4.4 to 5.4% Ti; 1.1 to 2.1% Nb; 0.005 to 0.025% B; 0.01 to 0.06% C; 0 to 0.6% Zr; 0.1 to 0.3% Hf; balance nickel. The article is characterized by a microstructure having an average grain size of from about 20 to 40 microns, with carbides, borides, and 0.3 to 0.4 micron-sized coarse gamma prime located at the grain boundaries, and 30 nanometer-sized fine gamma prime uniformly distributed throughout the grains. The alloys are suitable for use as turbine disks in gas turbine engines of the type used in jet engines, or for use as rim sections of dual alloy turbine disks for advanced turbine engines and are capable of operation at temperatures up to about 1500.degree. F. A method for achieving the desired properties in such turbine disks is also disclosed.

Abstract: An alloy is disclosed which has been found to lend itself particularly well to thermomechanical processing. The alloy is strengthened by precipitates similar to those of Inconel 718 but the alloy matrix of the composition is a nickel-chromium-cobalt matrix rather than the nickel-chromium-iron matrix of the Inconel alloy. Also the alloy has grains of average diameter of 35 .mu.m or larger. The fatigue resistance, tensile strength and the rupture strength of the alloy is improved to a remarkable degree as a result of the thermomechanical processing. The thermomechanical processing is carried out below the recrystallization temperature to prevent nucleation of fine grains. The residual strains from the thermomechanical processing or cold working provides the remarkably favorable combination of alloy properties which are found.

Abstract: Thermomechanical processing treatments for powder compacts formed from powdered superalloy compositions having a volume fraction of gamma prime greater than 35 percent are disclosed. Isothermal forging within critical ranges of strain rate and temperature is followed by supersolvus annealing and slow cooling treatments. An enlarged grain structure about 50 to 60 microns in size is produced that improves resistance to fatigue crack propagation in the superalloys.

Abstract: A low-alloy steel suitable for use in generator rotors and having a combination of good strength and impact energy with a high magnetic permeability is disclosed. The low-alloy steels are comprised of in weight percent; about 3.5 to 5.25 percent nickel, about 0.75 to 2.0, percent chromium, about 0.3 to 0.8 percent molybdenum, about 0.05 to 0.15 percent vanadium, about 0.1 to 0.28 percent carbon, about 0.03 to 0.1 percent niobium or titanium, and the balance substantially iron, wherein nickel, chromium, and carbon additions are balanced.

Abstract: Alloy compositions for nickel-base superalloys having the qualities of weldability, castability and forge-ability together with improved high temperature strength and rupture properties are disclosed. The weldability is improved by varying the Al, Ti, Nb and Ta content so as to insure that only the favorable .gamma." precipitates are formed in the alloy. The high temperature properties of the alloy compositions are optimized by controlling the content of the major alloying elements Co and Cr. Preferably the alloy is substantially free of Fe.

Abstract: This invention relates to corrosion resistant, austenitic, non-magnetic alloys. The alloys contain about 32 to 38% nickel, about 3 to 7% chromium, about 3 to 5% titanium, about 0.3 to 1.5% aluminum, about 0.5 to 1.5% molybdenum, an effective amount of vanadium, about 0.005 to 0.02% boron, up to about 0.02% carbon, and the balance substantially iron. The alloys are controlled temperature hot rolled and age annealed to provide strain hardening and precipitation strengthening to achieve yield strength objectives established for retaining rings in new high capacity generators. Yield strengths of at least about 200 ksi can be produced by the alloys of this invention making them suitable for use in new high capacity generators.

Abstract: A novel alloy is provided having approximately the following ingredient formula:______________________________________ Element Composition in weight % ______________________________________ Ni balance Cr 16 Co 18 Mo 5.00 W 5.00 Al 2.50 Ti 3.00 Nb 3.00 Zr 0.05 B 0.01 C 0.075 ______________________________________The alloy has a low solvus temperature for the .gamma.' precipitate thus facilitating metal processing and treatment and also forging of the metal. Fatigue crack propagation rate is remarkably low for metal samples cooled at rates of 20.degree. C./min to 200.degree. C./min.

Abstract: A novel nickel base superalloy is provided. The alloy is unique in having a high enough concentration of .gamma.' strengthening precipitate to provide a valuable set of physical properties and yet retain forgeability properties similar to those of alloys having lower concentration of precipitate.

Abstract: A novel heat treatment of a disk for a jet engine is provided. A temperature gradient is established on the disk to heat the inner portions to a temperature at which a subsolvus anneal takes place and to heat the outer portions to a temperature where a supersolvus anneal takes place. A reverse gradient is established from the inner portions of the disk during cooling after the anneal to cool the inner portions of the disk more rapidly than the outer portions so as to impart high tensile and fatigue strength to the inner portions and high temperature rupture life and crack growth resistance to the outer portions. A novel disk results.

Abstract: A method is provided for reducing fatigue crack propagation in nickel base superalloys. The method involves a supersolvus anneal in which essentially all .gamma.' precipitate phase is dissolved. The supersolvus anneal is folloed by slow cooling which is at a rate which substantially reduces time dependent fatigue crack growth but which preserves the strength of the alloy at a useful level for many superalloy applications.

Abstract: A novel alloy is provided having approximately the following ingredient formula:______________________________________ Element Composition in weight % ______________________________________ Ni balance Cr 10.0 Co 15.0 Mo 5.0 W 5.0 Al 3.5 Ti 3.0 Ta 7.2 Zr 0.03 B 0.03 C 0.03. ______________________________________The alloy has a solvus temperature of below 1200.degree. C. Fatigue crack propagation rate is low for metal samples cooled at rates of 50.degree. C./min to 200.degree. C./min. The alloy has uniquely high strength at temperatures at and above 1200.degree. F.

Abstract: A method has been discovered for reducing fatigue crack growth in nickel base superalloys. The method involves the step of forming a part to near net shape by forging or by other forming technique. The part is then heat treated to develop regular grains by recystallization. Grains of about 35 .mu.m average diameters are prepared. The part is then deformed at least 15% to achieve a net shape desired.

Abstract: A melt is provided having the formula(Ni.sub.0.76 Al.sub.0.24-x Nb.sub.x).sub.89.75 Fe.sub.10 B.sub.0.25.The melt is rapidly solidified as ribbon and the ribbon is annealed at about 1100.degree. C. Desirable properties are found when x is between 0.02 and 0.10.

Abstract: It had been found previously that tri-nickel aluminide compositions are quite sensitive to the ratio of nickel to aluminum in their ability to receive boron as a dopant. It has now been found that compositions which are relatively poor in the aluminum component can be doped more effectively with a combination of boron and zirconium. It has been found for the nickel aluminides which have lower concentrations of aluminum that the percent of zirconium and boron which can be added to the composition to effectively increase the strength of the alloys is favored by the lower aluminum ratio. The compositions which result are found to have significant strength properties not only at room temperature but at elevated temperatures based on tensile tests of the compositions.

Abstract: A melt is provided having the formula(Ni.sub.1-x Al.sub.x).sub.99-y Fe.sub.y B.sub.1The melt is rapidly solidified as ribbon and the ribbon is annealed at about 100.degree. C. Desirable properties are found when x is between 0.21 and 0.26 and y is between 5 and 15.

Abstract: A tri-nickel aluminide base alloy composition is provided with a desirable combination of tensile strength and ductility. The composition is prepared to include boron dopant in combination with relatively low percentages of carbon for the high increase in strength achieved. The composition has an Ll.sub.2 of crystalline structure. It is prepared by rapid solidification at a cooling rate of at least 10.sup.3 .degree. C. per second.