U.S. Department of Energy

General Electric Company

The United States of America As Represented by the Department of Energy

Jeffrey Allen Hawk

Paul D Jablonski

Robin Carl Schwant

Christopher J Cowen

Ling Yang

Martin Detrois

Malgorzata Ziomek-Moroz

Michael C Gao

Joseph H Tylczak

Alvaro A Rodriguez

This disclosure provides alloy compositions comprising the main constituent elements iron, nickel, cobalt, molybdenum, and chromium. In one embodiment, the alloy comprises 10.0 to 30.0 wt % iron; 30.0 to 60.0 wt % nickel; 10.0 to 25.0 wt % cobalt; 1.0 to 15.0 wt % molybdenum; 15.0 to 25.0 wt % chromium by weight; where the sum of iron and nickel is at least 50 wt %; and, where the balance comprises minor elements, the total amount of minor elements being about 5% or less by weight. The alloy compositions have use as coatings to protect metals and alloys from corrosion in extreme environments where corrosion is a major concern such as with exposure to sea water or sea water with CO.

High-performance corrosion-resistant high-entropy alloys

One or more embodiments relates to a method of casting a creep-resistant Ni-based superalloy and a homogenization heat treatment for the alloy. The method includes forming a feed stock having Nickel (Ni) and at least one of Chromium (Cr), Cobalt (Co), Aluminum (Al), Titanium (Ti), Niobium (Nb), Iron (Fe), Carbon (C), Manganese (Mn), Molybdenum (Mo), Silicon (Si), Copper (Cu), Phosphorus (P), Sulfur (S) and Boron (B). The method further includes fabricating the creep-resistant Ni-based superalloy in a predetermined shape using the feed stock and at least one process such as vacuum induction melting (VIM), electroslag remelting (ESR) and/or vacuum arc remelting (VAR).

Creep resistant Ni-based superalloy casting and method of manufacture for advanced high-temperature applications

The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, copper, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of MCcarbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650&#xb0; C.

Creep resistant high temperature martensitic steel

One or more embodiments relates to a method of producing an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y&#x2014;AlOlayer. The MCrAlY layer is comprised of a &#x3b3;-M solid solution, a &#x3b2;-MAl intermetallic phase, and Y-type intermetallics. The Y&#x2014;AlOlayer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the AlOlattice. The method comprises depositing an MCrAlY material on a substrate, applying an YOpaste, and heating the substrate in a non-oxidizing atmosphere at a temperature between 400-1300&#xb0; C. for a time sufficient to generate the Y&#x2014;AlOlayer. Both the MCrAlY layer and the Y&#x2014;AlOlayer have a substantial absence of YO, YAG, and YAP phases.

MCrAlY bond coat with enhanced yttrium

The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of MCcarbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650&#xb0; C.

One or more embodiments relates to an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y&#x2014;AlOlayer. The MCrAlY layer is comprised of a &#x3b3;-M solid solution, a &#x3b2;-MAl intermetallic phase, and Y-type intermetallics. The Y&#x2014;AlOlayer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the AlOlattice. Both the MCrAlY layer and the Y&#x2014;AlOlayer have a substantial absence of Y&#x2014;Al oxides, providing advantage in the maintainability of the Yttrium reservoir within the MCrAlY bulk. The MCrAlY bond coat may be fabricated through application of a YOpaste to an MCrAlY material, followed by heating in a non-oxidizing environment.

MCrAlY bond coat with enhanced Yttrium layer

Disclosed herein is a method of treating a component comprising solution treating the component for a period of about 4 to about 10 hours at a temperature of about 1750 to about 1850&#xb0; F.; cooling the component to a temperature of about 1490 to about 1520&#xb0; F. at an average rate of 1&#xb0; F./min to about 25&#xb0; F./min; stabilizing the component at about 1450 to about 1520&#xb0; F. for a period of from about 1 to about 10 hours; cooling the component to room temperature; precipitation aging the component by heating the component to a first precipitation aging temperature of about 1275 to about 1375&#xb0; F. for about 3 to about 15 hours; cooling the component at an average rate of 50 to about 150&#xb0; F./hour to a second precipitation aging temperature of about 1100 to about 1200&#xb0; F. for a time period of about 2 to about 15 hours; and cooling the component.

Heat treatment method and components treated according to the method

A method of heat treating an Ni-base superalloy article is disclosed. The method includes hot-working an article comprising an NiCrMoNbTi superalloy comprising, in weight percent, at least about 55 Ni to produce a hot-worked microstructure; solution treating the article at a temperature of about 1600&#xb0; F. to about 1750&#xb0; F. for about 1 to about 12 hours to form a partially recrystallized warm-worked microstructure; and cooling the article. The method also includes precipitation aging the article at a first precipitation aging temperature of about 1300&#xb0; F. to about 1400&#xb0; F. for a first duration of about 4 hours to about 12 hours; cooling the article to a second precipitation aging temperature; precipitation aging the article at a second precipitation aging temperature of about 1150&#xb0; F. to about 1200&#xb0; F. for a second duration of about 4 hours to about 12 hours; and cooling the article from the second precipitation aging temperature to an ambient temperature.

Method of heat treating a Ni-based superalloy article and article made thereby

The invention includes a turbine cover bucket of an alloy including carbon at less than approximately 0.04 weight percent, manganese at approximately 0.0-0.2 weight percent, silicon at approximately 0.0-0.25 weight percent, phosphorus at approximately 0.0-0.015 weight percent, sulfur at approximately 0.0-0.015 weight percent, chromium from approximately 20.0-23.0 weight percent, molybdenum from approximately 8.5-9.5 weight percent, niobium from approximately 3.25-4 weight percent, tantalum at approximately 0.0-0.05 weight percent, titanium from approximately 0.2-0.4 weight percent, aluminum from approximately 0.15-0.3 weight percent, iron from approximately 3.0-4.5 weight percent, and the remainder being nickel. The alloy is heat treated at 538&#xb0; C. to 760&#xb0; C. for up to 100 hours. A method of manufacturing the turbine bucket cover is also provided.

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Corvallis, OR, United States of America

Jeffrey Allen Hawk