Patent Application
20140199164
The present invention is directed to alloys and turbine components containing alloys. More specifically, the present invention is directed to nickel-based alloys.
Gas turbine components are subjected to both thermally, mechanically, and chemically hostile environments. For example, in the compressor portion of a gas turbine, atmospheric air is compressed, for example, to 10-25 times atmospheric pressure, and adiabatically heated, for example, to 800°-1250° F. (427° C.-677° C.), in the process. This heated and compressed air is directed into a combustor, where it is mixed with fuel. The fuel is ignited, and the combustion process heats the gases to very high temperatures, for example, in excess of 3000° F. (1650° C.). These hot gases pass through the turbine, where airfoils fixed to rotating turbine disks extract energy to drive the fan and compressor of the turbine, and the exhaust system, where the gases provide sufficient energy to rotate a generator rotor to produce electricity. To improve the efficiency of operation of the turbine, combustion temperatures have been raised.
Known directionally-solidified and equiaxed nickel-based alloys are used in gas turbine engines, such as, nozzles and buckets. The known alloys have a hafnium content that causes hafnium banding, core reaction, and hot tearing due to the high concentration of hafnium content. Lowering the hafnium content presents challenges to maintain mechanical properties and environmental resistance and has previously been believed to be undesirable.
To prevent the core reaction, attempts have been made to develop new core material and coatings. Attempts have been made to implement process modifications to reduce the time of a casting mold in a hot zone. Attempts of adding a wax pad on a pattern with a subsequent removal of hafnium banding by machining have been made. Attempts have been made to control hafnium content within a narrower range; however, such narrower ranges are not always economically and/or operationally feasible. Each of these attempts failed to balance the strengthening elements provided by hafnium.
A nickel-based alloy and a turbine component containing a nickel-based alloy that do not suffer from one or more of the above drawbacks would be desirable in the art.
In an exemplary embodiment, a nickel-based alloy includes, by weight, between about 0.8% and about 1.3% hafnium, between about 5.7% and about 6.4% aluminum, between about 7.0% and about 10.0% cobalt, up to about 0.1% carbon, up to about 8.7% chromium, up to about 0.6% molybdenum, up to about 9.7% tungsten, up to about 0.9% titanium, up to about 0.02% boron, up to about 0.1% manganese, up to about 0.06% silicon, up to about 0.01% phosphorus, up to about 0.004% sulfur, up to about 0.02% zirconium, up to about 1.8% niobium, up to about 0.1% vanadium, up to about 0.1% copper, up to about 0.2% iron, up to about 0.003% magnesium, up to about 0.002% oxygen, up to about 0.002% nitrogen, and a balance nickel.
In another exemplary embodiment, a turbine bucket includes an alloy, the alloy including between about 0.8% and about 1.3% hafnium, between about 5.7% and about 6.4% aluminum, between about 7.0% and about 10.0% cobalt, up to about 0.1% carbon, up to about 8.7% chromium, up to about 0.6% molybdenum, up to about 9.7% tungsten, up to about 0.9% titanium, up to about 0.02% boron, up to about 0.1% manganese, up to about 0.06% silicon, up to about 0.01% phosphorus, up to about 0.004% sulfur, up to about 0.02% zirconium, up to about 1.8% niobium, up to about 0.1% vanadium, up to about 0.1% copper, up to about 0.2% iron, up to about 0.003% magnesium, up to about 0.002% oxygen, up to about 0.002% nitrogen, and a balance nickel.
In another exemplary embodiment, a turbine nozzle includes an alloy, the alloy including between about 0.8% and about 1.3% hafnium, between about 5.7% and about 6.4% aluminum, between about 7.0% and about 10.0% cobalt, up to about 0.1% carbon, up to about 8.7% chromium, up to about 0.6% molybdenum, up to about 9.7% tungsten, up to about 0.9% titanium, up to about 0.02% boron, up to about 0.1% manganese, up to about 0.06% silicon, up to about 0.01% phosphorus, up to about 0.004% sulfur, up to about 0.02% zirconium, up to about 1.8% niobium, up to about 0.1% vanadium, up to about 0.1% copper, up to about 0.2% iron, up to about 0.003% magnesium, up to about 0.002% oxygen, up to about 0.002% nitrogen, and a balance nickel.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
Provided is an exemplary nickel-based alloy and a turbine component containing a nickel-based alloy. Embodiments of the present disclosure increase castability in comparison to alloys having higher concentrations of hafnium, increase creep strength in comparison to alloys having higher concentrations of hafnium, increase machinability in comparison to alloys having higher concentrations of hafnium, maintain mechanical properties of alloys having higher concentrations of hathium, maintain environmental resistance in comparison to alloys having higher concentrations of hafnium, increase yield of operational turbine components having the nickel-based alloy, decrease costs of producing the turbine components, or a combination thereof.
For example, embodiments of the nickel-based alloy include result in a gamma prime faction of greater than about 50% at 1800° F. (for example, between about 53% and about 62%, at about 53%, at about 54%, at about 55%, at about 59%, at about 60%, at about 61%, at about 62%, or any suitable range, sub-range, combination, or sub-combination thereof), a gamma prime solvus temperature of greater than about 2230° F. (for example, between about 2232° F. and about 2274° F., at about 2232° F., at about 2238° F., at about 2244° F., at about 2263° F., at about 2264° F., at about 2266° F., about 2267° F., at about 2271° F., about 2274° F., or any suitable range, sub-range, combination, or sub-combination thereof), a liquidus-solidus of less than about 95° F. (for example, between about 81° F. and about 89° F., less than or at about 83° F., less than or at about 84° F., less than or at about 85° F., less than or at about 86° F., less than or at about 87° F., less than or at about 88° F., less than or at about 89° F., or any suitable range, sub-range, combination, or sub-combination thereof), are devoid or substantially devoid of topologically-close-packed phases, or a combination thereof.
The nickel-based alloy is a portion of or all of any suitable component. In one embodiment, the nickel-based alloy forms a portion of or all of a turbine component or a turbine engine component. In one embodiment, the turbine component is a turbine nozzle, for example, as used in a power generation system. In another embodiment, the turbine component is a turbine blade or bucket, for example, as used in a power generation system.
The nickel-based alloy includes a directionally-solidified microstructure, an equiaxed microstructure, or a combination thereof. In one embodiment, the nickel-based alloy includes a directionally-solidified microstructure. The nickel-based alloy having the directionally-solidified microstructure provides increased castability and/or increased creep prevention in comparison to similar nickel-based alloys with a higher amount of hafnium. In one embodiment, the nickel-based alloy includes an equiaxed microstructure. The nickel-based alloy having the equiaxed microstructure provides increased castability and/or slightly lower creep prevention in comparison to similar nickel-based alloys with a higher amount of hafnium.
In one embodiment, the nickel-based alloy includes, by weight, between about 0.8% and about 1.3% hafnium, between about 5.7% and about 6.4% aluminum, between about 7.0% and about 10.0% cobalt, up to about 0.1% carbon, up to about 8.7% chromium, up to about 0.6% molybdenum, up to about 9.7% tungsten, up to about 0.9% titanium, up to about 0.02% boron, up to about 0.1% manganese, up to about 0.06% silicon, up to about 0.01% phosphorus, up to about 0.004% sulfur, up to about 0.02% zirconium, up to about 1.8% niobium, up to about 0.1% vanadium, up to about 0.1% copper, up to about 0.2% iron, up to about 0.003% magnesium, up to about 0.002% oxygen, up to about 0.002% nitrogen, and a balance nickel.
In one embodiment, the hafnium is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.8% and about 1.1%. In other embodiments, the hafnium is present and is at a concentration of, by weight, up to about 1.1%, up to about 1.3%, between about 1.1% and about 1.3%, between about 0.8% and about 1.1%, between about 0.9% and about 1.1%, between about 0.8% and about 0.9%, between about 1.0% and about 1.1%, about 0.8%, about 0.9%, about 1.0%, about 1.1%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the hafnium is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 1.1% and about 1.3%. In other embodiments, the hafnium is present and is at a concentration of, by weight, up to about 1.3%, between about 1.1% and about 1.2%, between about 1.2% and about 1.3%, about 1.1%, about 1.2%, about 1.3%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the nickel-based alloy includes tantalum and the tantalum is present at a concentration of, by weight, between about 3.3% and about 3.5%. In other embodiments, the tantalum is present and is at a concentration of, by weight, up to about 0.1%, up to about 1.6%, up to about 2.8%, up to about 3.5%, between about 3.1% and about 3.3%, between about 3.3% and about 3.5%, between about 2.5% and about 2.8%, between about 1.4% and about 1.6%, about 0.1%, about 1.4%, about 1.6%, about 2.5%, about 2.8%, about 3.3%, about 3.5%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the nickel-based alloy is substantially devoid of or completely devoid of tantalum.
In one embodiment, the nickel-based alloy includes niobium and the niobium is present at a concentration of, by weight, between about up to about 1.8%. In other embodiments, the tantalum is present and is at a concentration of, by weight, up to about 0.1%, between about 0.15% and about 0.25%, between about 1.6% and about 1.8%, about 0.1%, about 0.2%, about 1.6%, about 1.7%, about 1.8%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, tantalum or niobium are substituted for one another at a ratio of one to one.
In one embodiment, the aluminum is present at a concentration of, by weight, between about 5.7% and about 6.0%, between about 6.0% and about 6.4%, between about 5.7% and about 6.2%, about 5.7%, about 5.9%, about 6.1%, about 6.4%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the cobalt is present at a concentration of, by weight, between about 7.0% and about 9.0%, between about 8.0% and about 10.0%, between about 7.5% and about 9.5%, between about 8.5% and about 9.5%, about 7.0%, about 8.0%, about 9.0%, about 10.0%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the carbon is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.07% and about 0.1%, between about 0.08% and about 0.09%, between about 0.09% and about 0.1%, between about 0.07% and about 0.09%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the chromium is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 8.0% and about 8.7%, between about 8.0% and about 8.3%, between about 8.4% and about 8.7%, between about 8.2% and about 8.5%, about 8.0%, about 8.3%, about 8.5%, about 8.7%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the molybdenum is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.1% and about 0.6%, between about 0.3% and about 0.5%, between about 0.4% and about 0.6%, about 0.4%, about 0.5%, about 0.6%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the tungsten is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 9.3% and about 9.7%, between about 9.3% and about 9.5%, between about 9.5% and about 9.7%, about 9.3%, between about 9.4%, about 9.5%, about 9.6%, about 9.7%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the titanium is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.1% and about 0.9% titanium, between about 0.1% and about 0.5%, between about 0.5% and about 0.9%, between about 0.3% and about 0.7%, between about 0.7% and about 0.9%, about 0.3%, about 0.5%, about 0.7%, about 0.8%, about 0.9%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the boron is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.01% and about 0.02%, about 0.01%, about 0.02%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, manganese is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.05% and about 0.1%, about 0.02%, about 0.07%, 0.07% and about 0.1%, about 0.05%, about 0.07%, about 0.1%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the silicon is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.01% and about 0.06%, between about 0.03% and about 0.04%, between about 0.03% and about 0.06%, about 0.02%, about 0.04%, about 0.06%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the phosphorus is present in the nickel-based alloy, for example, at a concentration of, by weight, up to about 0.01%, between about 0.005% and about 0.01%, about 0.002%, about 0.007%, 0.007% and about 0.01%, about 0.005%, about 0.007%, about 0.01%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the sulfur is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.001% and about 0.004%, between about 0.002% and about 0.004%, between about 0.003% and about 0.004%, about 0.001%, about 0.002%, about 0.003%, about 0.004%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the zirconium is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.01% and about 0.02%, about 0.01%, about 0.02%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the vanadium is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.05% and about 0.1%, about 0.02%, about 0.07%, 0.07% and about 0.1%, about 0.05%, about 0.07%, about 0.1%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the copper is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.05% and about 0.1%, about 0.02%, about 0.07%, 0.07% and about 0.1%, about 0.05%, about 0.07%, about 0.1%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the iron is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.01% and about 0.02%, about 0.01%, about 0.02%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the magnesium is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.001% and about 0.003%, between about 0.002% and about 0.003%, about 0.001%, about 0.002%, about 0.003%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the oxygen is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.001% and about 0.002%, about 0.001%, about 0.002%, or any suitable combination, sub-combination, range, or sub-range thereof.
In one embodiment, the nitrogen is present in the nickel-based alloy, for example, at a concentration of, by weight, between about 0.001% and about 0.002%, about 0.001%, about 0.002%, or any suitable combination, sub-combination, range, or sub-range thereof.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
