Nickel-based superalloy, process therefor, and components formed therefrom

Abstract

A gamma prime nickel-based superalloy suitable for producing structural components (10), for example, turbine disks (10) and other turbomachinery components. The superalloy comprises an intentional amount of iron of up to 2.0% and is preferably capable of exhibiting structural properties comparable to nickel-based superalloys without iron. The superalloy can be made using processes that lend themselves to advantageous scrap and revert usage of iron-containing alloys. The superalloy is free of an observable amount of sigma phase.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 670,634, filed Jul. 12, 2012, the contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]The present invention generally relates to alloy compositions, and more particularly to superalloys suitable for components requiring a polycrystalline microstructure and both high temperature dwell and / or creep capabilities, for example, turbine disks of gas turbine engines. Such alloys may also be useful in a multi-grain directionally solidified form or single crystal form.[0003]The turbine section of a gas turbine engine is located downstream of a combustor section and contains a rotor shaft and one or more turbine stages, each having a turbine disk (rotor) mounted or otherwise carried by the shaft, and turbine blades mounted to and radially extending from the periphery of the disk. Components within the combustor and turbine sections are oft...

AI Technical Summary

Benefits of technology

This patent describes a new type of superalloy that can be made using a specific process. This superalloy has similar properties and capabilities to other superalloys, but it allows for more iron content. This means that it can be made more economically and efficiently, with less material waste and higher utilization of scrap and equipment. Additionally, it has lower personnel and time requirements. Overall, this patent provides a way to make a high-quality superalloy that is more cost-effective and efficient to produce.

Problems solved by technology

However, the ability to tolerate the significant iron content of IN718 a limiting factor in cost-effective revert and scrap utilization for R88DT, because as described above, R88DT does not contain iron as a constituent.

Sigma phase is a well-known topologically close-packed (TCP) phase which can adversely affect the mechanical capabilities of a gamma prime nickel-base alloy.

Hence, scrap or revert utilization for use in the production of R88DT would carry with it a high probability of iron contamination and sigma phase formation that is not desirable in R88DT.

Unfortunately, such methods have significant limitations in terms of additional personnel training and maintaining separate chips or containers.

In addition, there can be contamination from melting equipment or melt-handling or machining equipment that may have been previously used for the production of an iron-containing alloy, in which case extensive cleaning is required of equipment between switching over to production of different alloys.

The above mentioned methods of preventing iron contamination result in loss of valuable material and / or production efficiency.

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