Abstract: Fatigue crack growth-resistant articles are made from powder metal or cast and wrought gamma prime precipitation strengthened nickel-base superalloy material, wherein a relatively high predetermined minimum strain rate, .epsilon..sub.min, is employed during hot working at or near the alloy's recrystallization temperature; or alternatively a relatively high strain level, .epsilon..sub.min, is employed during cold or warm working at temperatures below the alloy's recrystallization temperature. The worked articles are characterized by a uniform fine grain size, and grains which coarsen uniformly after heating at the supersolvus solutioning temperature, thereby alleviating non-uniform grain growth within the material.

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: Two pieces of metal are bonded together at a surface by placing the two pieces into contact at the surface and forging the two pieces in a die which causes substantial displacement of the metal originally at the surface in a direction parallel to and outwardly from the edges of the surface. In this way, many of the defects which are potentially present at the original surface are displaced with moving metal away from the original contact between the two pieces of metal into sacrificial ribs and the remaining defects are exposed to significant strain. A portion of the displaced metal which contains many of the defects and which forms the sacrificial ribs is removed from the resulting bonded work piece as the sacrificial ribs are removed from the work piece. The result is a bond with superior properties and with a bond surface which can be located very precisely.

Abstract: An article of manufacture having at least a first and a second part, each part having different mechanical properties, compositions, microstructures or combinations thereof, being joined together using a forging process to yield a substantially defect-free joint region. The article in the form of a turbine disk is particularly suited for use in a gas turbine engine in which the hub or inner portion must be resistant to low cycle fatigue and have high strength, while the rim or outer portion must be resistant to stress rupture failure and creep failure.