Cannon-Muskegon Corporation

Kenneth Harris

Gary L Erickson

Jacqueline B Wahl

John M Eridon

Steven L Sikkenga

A low rhenium nickel-base superalloy for single crystal casting that exhibits excellent high temperature creep resistance, while also exhibiting other desirable properties for such alloys, comprises 5.60% to 5.80% aluminum by weight, 9.4% to 9.9% cobalt by weight, 4.9% to 5.5% chromium by weight, 0.08% to 0.35% hafnium by weight, 0.50% to 0.70% molybdenum by weight, 1.4% to 1.6% rhenium by weight, 8.1% to 8.5% tantalum by weight, 0.60% to 0.80 titanium by weight, 7.6 to 8.0% tungsten by weight the balance comprising nickel and minor amounts of incidental impurity elements.

Low rhenium single crystal superalloy for turbine blades and vane applications

A nickel-base superalloy for single crystal casting of components exhibiting excellent creep and rupture properties at high temperature and stresses, and which exhibits excellent phase stability contains 5.60% to 5.80% by weight of aluminum; 9.4% to 9.8% by weight of cobalt; 3.2% to 3.9% by weight of chromium; 7.8% to 8.5% by weight of tantalum; 5.3% to 5.7% by weight of tungsten; 0.50% to 0.70% by weight of molybdenum; 4.3% to 4.9% by weight of rhenium; 0.75% to 0.90% by weight of titanium; 0.08% to 0.15% by weight of hafnium; less than 1.1% by weight of tramp elements other than aluminum, cobalt, chromium, tantalum, tungsten, molybdenum, rhenium, titanium and nickel; and balance nickel.

High strength single crystal superalloy

A single crystal casting having substantially improved high-temperature oxidation resistance, hot corrosion (sulfidation) resistance, and resistance to creep under high temperature and high stress is characterized by an as-cast composition comprising a maximum sulfur content of 0.5 ppm by weight, a maximum phosphorus content of 20 ppm by weight, a maximum nitrogen content of 3 ppm by weight, a maximum oxygen content of 3 ppm by weight, and a combined yttrium and lanthanum content of 5-80 pm by weight. It has been discovered that careful control of the deleterious impurities, particularly sulfur, phosphorus, nitrogen and oxygen, in combination with a carefully controlled addition of yttrium and/or lanthanum provides unexpected improvements in corrosion and oxidation resistance, while also enhancing high-temperature, high-stress resistance to creep, without any detrimental effects on other mechanical properties, processing or producability, particularly castability.

Low sulfur nickel-base single crystal superalloy with PPM additions of lanthanum and yttrium

A nickel-base superalloy that is useful for making single crystal castings exhibiting outstanding stress-rupture properties, creep-rupture properties, and an increased tolerance for grain defects contains, in percentages by weight, from about 4.7% to about 4.9% chromium, (Cr), from about 9% to about 10% cobalt (Co), from about 0.6% to about 0.8% molybdenum (Mo), from about 8.4% to about 8.8% tungsten (W), from about 4.3% to about 4.8% tantalum (Ta), from about 0.6% to about 0.8% titanium (Ti), from about 5.6% to about 5.8% aluminum (Al), from about 2.8% to about 3.1% rhenium (Re), from about 1.1% to about 1.5% hafnium (Hf), from about 0.06% to about 0.08% carbon (C), from about 0.012% to about 0.020% boron (B), from about 0.004% to about 0.010% zirconium (Zr), the balance being nickel and incidental impurities. The nickel-base superalloy provides improved casting yield and reduce component cost due to a reduction in rejectable grain defects as compared with conventional directionally solidified casting alloys and conventional single crystal alloys.

Superalloy for single crystal turbine vanes

A nickel-base superalloy that exhibits outstanding mechanical properties under high temperature and high strain conditions when cast in an equiaxed and/or directionally solidified, columnar grain structure, and which exhibits increased grain boundary strength and ductility while maintaining microstructural stability includes, in percentages by weight, 5-6 chromium, 9-9.5 cobalt, 0.3-0.7 molybdenum, 8-9 tungsten, 5.9-6.3 tantalum, 0.05-0.25 titanium, 5.6-6.0 aluminum, 2.8-3.1 rhenium, 1.1-1.8 hafnium, 0.10-0.12 carbon, 0.010-0.024 boron, 0.011-0.020 zirconium, with the balance being nickel and incidental impurities. The superalloys of this invention are useful for casting gas turbine engine components exhibiting significantly improved low cycle fatigue life, improved airfoil high temperature stress rupture life, significantly reduced life cycle cost, and longer useful life.

Nickel-base superalloy for high temperature, high strain application

An improved nickel-based single crystal superalloy has both an extremely low sulphur content and a very low lanthanum, cerium, or lanthanum plus yttrium, or cerium plus yttrium, or content, whereby the amount while very low, is sufficient to react with the remaining available sulphur in the alloy and with sulphur from the fuel used in engine operation, such that the very thin, protective scale layer of aluminum oxide formed on the surfaces of the nickel-based alloy parts exposed to the very high temperatures incident in high efficiency turbine engines, will afford effective, long-life protection for the surfaces of these engine components, through the virtual elimination of spalling of the aluminum oxide scale during cyclic engine operations.

Low yttrium, high temperature alloy

A nickel base superalloy for columnar grain, directional solidification which contains Re for strength and creep resistance, and substantially eliminates the use of Zr and minimizes Si to prevent DS grain boundary cracking. The creep- and stress-rupture properties, which approach nickel base superalloy single crystal performance, are achieved without the use of high temperature gamma prime solution treatment.

Low carbon directional solidification alloy

A single crystal nickel alloy is provided having many of the foundry and performance characteristics of the higher density, single crystal, nickel base super alloys from which the vanes and blades are cast for high performance turbine aircraft engines. The lower density of this alloy permits its use for rebuilding and upgrading the performance of older turbine aircraft engines of designs which cannot withstand the centrifugal forces generated by the new state of the art higher density single crystal super alloys. The alloy for the first time provides a lower density single crystal alloy capable of heat treatment to stabilize its microstructure for high temperature, high stress use. It also provides for the first time a lower density alloy having acceptable resistance to the effects of high temperature sulfidation, salt corrosion and also to have good coating life. By significant changes in the alloy composition the resulting alloy has creep rupture and stress rupture performance characteristics similar to that of the high density nickel base super alloys while maintaining a density characteristic of equiaxe alloys.

Low density single crystal super alloy

Single crystal nickel-base superalloy having very fine gamma prime after heat treatment in a temperature range permitting total gamma prime solutioning without incipient melting. Component of the heat treated alloy has exceptional resistance to creep under high temperature and stress, particularly in that part of the creep curve representing one percent or less elongation. The alloy exhibits exceptionally low steady-state creep rate.

Single crystal alloy technology

The alloy is a nickel base, superalloy specifically intended for the making of castings which consist of a single crystal. The castings are intended for use under extreme conditions of high temperature and stress. The alloy, for the first time, achieves the desired characteristics of phase stability, high stress-rupture strength and resistance to oxidation while maintaining a sufficient temperature differential between gamma prime solvus and incipient melting temperatures, that it is practical to solution heat treat without unacceptable percentages of rejects due to failure either to completely solution the primary coarse gamma prime or to initiation of incipient melting. In a modified form the coated oxidation/corrosion resistance of the alloy is increased by the addition of a trace quantity of hafnium.

Single crystal (single grain) alloy

An improved alloy for use in directional solidification casting is disclosed in which the proportions of carbon, zirconium, tungsten and molybdenum have been changed to produce a new ultra high strength casting alloy free of the problem of grain boundary cracking which has been encountered in the production of directional solidification castings of this type of alloy and to minimize M.sub.6 C plate phase formation in turbine blades under high temperature conditions over extended operating periods. In addition there is disclosed the unexpected characteristic of the alloy's substantial increase in fracture toughness and tensile ductility under extreme operating conditions.

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Spring Lake, MI, United States of America

Kenneth Harris