General Electric Company

Wyman-gordon Company

Michael E Sauby

Richard G Menzies

Sulekh C Jain

Bruce P Bardes

Swami Ganesh

Daniel D Krueger

Keh-Minn Chang

Jeffrey Francis Wessels

Allen J Paxson

Robert D Kissinger

Hugo E Delgado

Timothy E Howson

Wilford H Couts, Jr

John Michael Hyzak

Steven H Reichman

Daniel D Kruger

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.

Method for making fatigue crack growth-resistant nickel-base article

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.

Dual alloy turbine disk

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. This system is particularly appropriate for forming dual-alloy high-pressure turbine disks for gas turbines in which an annular peripheral ring of a second super-alloy is bonded to a central core of a first super-alloy. The system is particularly effective if, prior to forging, surfaces to be bonded are closely shape-conforming, are very clean, and are diffusion-bonded using hot isostatic pressing while the surfaces are gas-free. The sacrificial ribs are formed by vents in the impression of the forging dies. The vents are adjacent to the outer edges of the bond surface. The system may be accomplished by using one or more strikes of the same dies, or may include multiple strikes in which only one side of the bond is vented during each strike.

Dual-alloy disk system

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.

Method of manufacturing dual alloy turbine disks

Growing community of inventors

Cincinnati, OH, United States of America

Michael E Sauby