Nickel base gamma prime strengthened superalloy

Abstract

A nickel base gamma prime strengthened superalloy with a unique blend of high hot corrosion resistance, high oxidation resistance, high coating compatibility, good weldability, high phase stability and at least moderate creep resistance is disclosed. The composite includes: Up to 20 wt % Co, between 17 and 21 wt % Cr, between 2 and 5 wt % of Mo+W+Re, at most 2 wt % Mo, between 4 and 4.7 wt % AL, between 3 and 7 wt % Ta, 0.01 and 0.2 wt % Ta, between 0.01 and 0.3 wt % of C+Zr+B between 0.05 and 1 wt % Hf, between 0.05 and 1 wt % Si, and between 0.01 and 0.2 wt % of the sum of rare earths such as SC, Y, the actinides and the lanthanides. The composition is intended for use as base alloy for moderately stressed hot components and as filler alloy for cladding and weld repair in moderately stressed parts of hot components.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is the US National Stage of International Application No. PCT / EP2009 / 052341, filed Feb. 27, 2009 and claims the benefit thereof. The International Application claims the benefits of European Patent Office application No. 08003904.3 EP filed Mar. 3, 2008. All of the applications are incorporated by reference herein in their entirety.FIELD OF INVENTION[0002]The present invention relates to a nickel-base gamma prime strengthened superalloy. It further relates to its use in hot components such as, but not restricted to, vanes, heat shields, sealings and combustor parts in gas turbines. It further relates to its use as filler alloy for cladding and repair of hot components such as, but not restricted to, blades, vanes, heat shields and combustor parts in gas turbines. It further relates to its use in equiaxed, directionally solidified or monocrystalline form.BACKGROUND OF INVENTION[0003]Gamma prime strengthened nickel-base sup...

AI Technical Summary

Benefits of technology

[0042]Consider a component and a hot spot on said component. A base alloy with this blend of properties would provide a higher cyclic life for an applied thermal barrier coating than an Ti rich alloy such as IN939, and, would provide a longer residual life if spallation occurs.

[0043]Consider further a component cast in a Ti rich alloy such as IN939 and protected by a thermal barrier coating, and that said component has suffered local spallation of this thermal barrier coating at a hot spot, leading to oxidation damage. Weld-repair with a filler alloy having the said blend of properties would result in locally improved resistance to spallation of the thermal barrier coating when re-applied after weld-repair, and, increased residual life if spallation occurs.

[0044]Base and filler alloys with this blend of properties will also provide better robustness in corrosive environments than high Mo content alloys such as U-700, or low Cr content alloys such as Mar M-247. Further, they will provide better dimensional stability than a weak alloy such as Haynes-214.

[0045]Consider further that in a weld, mixing during welding and subsequent interdiffusion in service will occur. In particular, Ti may diffuse into the filler alloy in the case of Ti rich base alloys such as IN939. It would be an advantage to have a filler alloy which retained adequate phase stability also while having absorbed some Ti, to avoid TCP precipitation. TCP ph...

Problems solved by technology

Consider further a component cast in a Ti rich alloy such as IN939 and protected by a thermal barrier coating, and th...

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