Turbine component formed from titanium alloy

Abstract

A turbine component is provided that includes a titanium alloy modified with Ti-64. This modification retains the properties of the desired Ti-64 (e.g., relatively isotropic properties, relatively low density, resistance to FOD, repairability, and low cost) while improving thick cross-sectional strength, HCF capability, creep strength, and low deformation after FOD to approach those beneficial aspects of Ti-17 and Ti-6246. Methods of forming such turbine components are also provided.

Description

[0001] Priority information

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 506,614, filed on June 7, 2023, which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0003] The present application generally relates to components formed of titanium alloys. In particular, the components formed of titanium alloys disclosed in the present application are particularly suitable for use in rotating machines, such as gas turbines. Background Art

[0004] At least some known rotating machines, such as but not limited to steam turbine engines and / or gas turbine engines, include various rotor assemblies, such as fan assemblies, compressors, and / or turbines (all of which include rotor assemblies). At least some known rotor assemblies include, for example, but not limited to, disks, shafts, spools, blade disks ("blade disks"), seals and / or blade integration rings ("blings"), and individual dovetail linked blades. Depending on the axial position in the gas turbine engine, such components may be subject to different temperatures.

[0005] For example, during operation, at least some known gas turbine engines may be subject to an axial temperature gradient extending along a central longitudinal axis of the engine. Typically, gas turbine engine components are exposed to lower operating temperatures toward the front of the engine and higher operating temperatures toward the rear of the engine. As a result, known rotor assemblies and / or rotor components are typically manufactured from materials that are capable of withstanding the expected highest temperature at the expected location within the engine.

[0006] To accommodate different temperatures, different engine components have been forged from different alloys having different material properties that enable the component to withstand different expected maximum radial and / or axial temperatures. More specifically, known rotating assemblies and / or rotating components are typically forged from a single alloy that is capable of withstanding the expected maximum temperature of the entire rotating assembly and / or rotating component. For example, Ti-17 (Ti-5Al-4Mo-4Cr-2Sn-2Zr), Ti-6246 (Ti-6Al-2Sn-4Zr-6Mo), and Ti-64 (Ti-6Al-4V) may be used for rotating components within a gas turbine engine, depending on the relative position of the part in the engine.

[0007] Ti-64 is an alpha / beta processed titanium alloy that is highly manufacturable, has relatively isotropic properties, has relatively low density, is resistant to foreign object damage (FOD), is relatively easy to repair, and has relatively low cost. However, Ti-64 has limited thick section strength and high cycle fatigue (HCF) capability. In contrast, Ti-17 and Ti-6246 are beta treated, are not as easy to manufacture, have greater anisotropy (especially ductility) due to the beta treatment, have higher density, are not resistant to FOD, are not as easy to repair, and cost more. However, Ti-17 and Ti-6246 have good thick section strength, have good HCF capability, and have better temperature capabilities than Ti-64.

[0008] Therefore, there is a need for a low-cost titanium alloy that has the good qualities of Ti-64 (e.g., relatively isotropic properties, relatively low density, FOD resistance, repairability) and some of the advantages of Ti-17 and Ti-6246 (e.g., thick section strength and HCF). Summary of the invention

[0009] The present invention relates to a turbine component, which comprises a titanium alloy, wherein the titanium alloy comprises: 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen; and the balance is titanium, wherein the titanium alloy is substantially free of copper.

[0010] The present invention also relates to a turbine component comprising a titanium alloy, wherein the titanium alloy comprises: 5.50 wt% to 6.90 wt% aluminum; 3.50 wt% to 4.50 wt% vanadium; 0.01 wt% to 0.03 wt% carbon; 0.20 wt% to 0.70 wt% iron; 1.00 wt% to 1.50 wt% molybdenum; 0.10 wt% to 0.30 wt% silicon; up to 0.21 wt% oxygen; up to 0.016 wt% nitrogen; and the balance is titanium, wherein the presence of Al, O, Fe, Si, and Mo results in The 0.2% yield strength at 23°C predicted by the following formula is ≥1000 MPa: 469.3+48.8×Al(wt%)+748×O(wt%)+96.1×Fe(wt%)+188×Si(wt%)+57.7×Mo(wt%), or the amount of Fe, Si and Mo present results in a plastic elongation % at 23°C predicted by the following formula ≥15.0%: 10^(1.149+0.211×Fe(wt%)–0.514×Si(wt%)+0.076×Mo(wt%)).

[0011] On the other hand, the present invention is directed to a method for forming a turbine component, the method comprising: forging a titanium alloy into a turbine component, wherein the titanium alloy comprises: 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen (e.g., up to 0.015wt% nitrogen); and the balance is titanium, wherein the titanium alloy is substantially free of copper.

[0012] The present invention also relates to a method for forming a turbine component, the method comprising: forging a titanium alloy into a turbine component, wherein the titanium alloy comprises: 5.50 wt% to 6.90 wt% aluminum; 3.50 wt% to 4.50 wt% vanadium; 0.01 wt% to 0.03 wt% carbon; 0.20 wt% to 0.70 wt% iron; 1.00 wt% to 1.50 wt% molybdenum; 0.10 wt% to 0.30 wt% silicon; up to 0.21 wt% oxygen; up to 0.016 wt% nitrogen (e.g., up to 0.015 wt% nitrogen); and the balance is titanium, wherein Al, O , Fe, Si, and Mo are present in amounts resulting in a 0.2% yield strength at 23°C of ≥1000 MPa as predicted by the following formula: 469.3+48.8×Al(wt%)+748×O(wt%)+96.1×Fe(wt%)+188×Si(wt%)+57.7×Mo(wt%), and / or wherein the Fe, Si, and Mo are present in amounts resulting in a plastic elongation at 23°C of ≥15.0% as predicted by the following formula: 10^(1.149+0.211×Fe(wt%)–0.514×Si(wt%)+0.076×Mo(wt%)). BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For those skilled in the art, a complete and effective disclosure of the present disclosure, including the best mode thereof, is set forth in the specification with reference to the accompanying drawings, wherein:

[0014] Figure 1 is a cross-sectional view of a gas turbine engine according to an exemplary aspect of the present disclosure;

[0015] Figure 2 is suitable for gas turbine engines (such as Figure 1 An isometric view of a blade disk of an example of a turbine component shown in FIG. 1 ; and

[0016] Figure 3 Cross-sections of a blade disk at two stages showing the possible locations of the weld zone, e.g. Figure 2of the blade disk.

[0017] definition

[0018] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. In addition, unless otherwise stated, all implementations described herein should be considered exemplary.

[0019] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0020] In a context such as “at least one of A, B, and C,” the term “at least one of” means only A, only B, only C, or any combination of A, B, and C.

[0021] The phrases "X to Y," "from X to Y," and "between X and Y" all refer to numerical ranges that include the endpoints (i.e., to numerical ranges that include X and Y). Here and throughout the specification and claims, range limitations are combined and interchanged, and such ranges are identified and include all subranges contained therein unless the context or language indicates otherwise. For example, all ranges disclosed herein include the endpoints, and the endpoints are independently combinable with each other.

[0022] As used herein, the term "substantially free" should be understood as completely free of the ingredient, or containing trace amounts of the ingredient. "Trace amount" refers to a quantitative level of a chemical ingredient that is barely detectable and that has no benefit to the functional or aesthetic properties of the subject composition. The term "substantially free" also includes completely free.

[0023] The term "turbomachine" refers to a machine that includes one or more compressors, a heat generating section (eg, a combustion section), and one or more turbines that together produce a torque output.

[0024] The term "gas turbine engine" refers to an engine having a turbine as all or part of its power source. Example gas turbine engines include turbofan engines, turboprop engines, turbojets, turboshaft engines, etc., as well as hybrid-electric versions of more than one of these engines.

[0025] Chemical elements are discussed in this disclosure using their common chemical abbreviations, such as those commonly found in the periodic table of elements. For example, hydrogen is represented by its common chemical abbreviation H; helium is represented by its common chemical abbreviation He; and so on.

[0026] The term "yield strength" refers to the stress at which a material begins to deform plastically (permanently) without increasing load. It is the point on the stress-strain curve where the material changes from elastic deformation (reversible) to plastic deformation (irreversible). The 0.2% yield strength is the strength measured at 0.2% plastic strain above the yield strength. It is easier to measure and more repeatable than the yield strength. The 0.2% yield strength is an important parameter for determining the structural integrity and stability of a material under load.

[0027] The term "ultimate tensile strength" ("UTS") is the maximum stress a material can withstand before it ruptures or breaks. It is the highest point on the stress-strain curve and represents the maximum strength of the material under tensile load. Once the UTS is reached, the material will neck (locally deform) and eventually fail.

[0028] The term "plastic elongation" refers to the ability of a material to deform plastically without breaking under tensile stress. It is an important mechanical property that measures the extent to which a material can be permanently deformed without breaking. Ductile materials undergo large plastic deformations before failure, while brittle materials tend to break without significant deformation. Plastic elongation is usually measured as the percentage increase in the length between two marks on the gauge before the test and the final distance between the two marks after the test is completed and the two broken halves of the specimen are reassembled. The higher the plastic elongation, the greater the ductility, as this indicates that the metal can deform significantly before breaking. Conversely, the lower the plastic elongation, the lower the ductility, which means that the metal is more brittle and more likely to break without significant plastic deformation.

[0029] "Reduction in Area" (also expressed as "%RA") refers to a measurement that quantifies the degree of deformation or plastic flow that occurs in a metal specimen during a mechanical test. When a metal specimen is subjected to a tensile force, it undergoes plastic deformation in the form of elongation and a reduction in cross-sectional area. Reduction in Area is a measure of the reduction in cross-sectional area of ​​the specimen after it breaks or fails during a test. Reduction in Area is typically expressed as a percentage and calculated using the following formula: Reduction in Area = [(Original Cross-sectional Area - Final Cross-sectional Area) / Original Cross-sectional Area] x 100. The greater the reduction in area, the greater the ductility, as this indicates that the metal will deform significantly before breaking. Conversely, the smaller the reduction in area, the lower the ductility, meaning that the metal is more brittle and more likely to break without significant plastic deformation.

[0030] The published values ​​for 0.2% yield strength, ultimate tensile strength, plastic elongation, and reduction of area are measured at room temperature (i.e., 20°C to 25°C) in accordance with ASTM E8 / E8M (also known as Standard Test Methods for Tensile Testing of Metallic Materials). ASTM E8 / E8M is a widely used standard in the field of materials testing (including alloy characterization) that provides guidelines for conducting tensile tests to determine the mechanical properties of metallic materials. With the exception of ASTM E8 / E8M, all tensile tests are conducted at a controlled strain rate of 0.005 inches / inch ± 0.002 inches / inch per minute. After the 0.2% yield point is reached and the load stabilizes, the crosshead speed is 0.05 ± 0.01 inches / inch of the reduced length of the specimen per minute. Plastic elongation and %RA are measured using the "fitting method" in which the fracture surfaces of the failed specimens are fitted together to measure the length change and reduced cross-sectional area required to calculate these parameters. All tensile tests are conducted on bars having a gage diameter of at least 0.14" and a gage length of at least 0.75".

[0031] "Ballistic impact resistance" refers to the ability of a material to resist penetration or deformation caused by a projectile or high-speed impact. This is particularly important in applications where protection against bullets, shrapnel or other projectiles is required. Materials with high ballistic impact resistance are designed to absorb and dissipate impact energy, reducing damage caused by projectiles. Resistance to ballistic impact damage or foreign object damage is measured using a compression ballistic test apparatus that fires a 0.36 g, 55 Rockwell C hardness, approximately 4.45 mm diameter ball bearing chrome steel alloy into a test alloy target with a sample thickness of 0.762 mm at a velocity of about 182.9 m / s to about 304.8 m / s. The extent of damage is quantified by summing the total radial crack lengths of cracks initiated at the impact site. For the avoidance of doubt, only the radial crack lengths are summed without taking into account any circumferential cracks associated with the impact site.

[0032] The term "weight %" (abbreviated herein as wt%) refers to the concentration of a specific element content in a titanium alloy. Weight % indicates the ratio of the weight of the element relative to the total weight of the titanium alloy, expressed as a percentage. Weight % is calculated by dividing the weight of the element by the total weight of the titanium alloy and multiplying the result by 100. DETAILED DESCRIPTION

[0033] The present embodiments of the present disclosure will now be described in detail, one or more examples of which are shown in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Similar names in the drawings and the specification have been used to refer to similar parts in the present disclosure.

[0034] Turbine components are generally provided that are composed of a titanium alloy modified from Ti-64 to maintain the desired properties of Ti-64 (e.g., relatively isotropic properties, relatively low density, tolerance to FOD, repairability, and low cost) while improving thick section strength, HCF capability, creep strength, and low deformation after FOD to approach those beneficial aspects of Ti-17 and Ti-6246. The cost of the newly modified Ti-64 alloy can be minimized by designing the composition so that a high percentage of widely available Ti-64 recycled material can be used. In addition, the billet and forging processing methods can be kept as close to Ti-64 as possible to minimize costs while allowing large-scale production of such turbine components from titanium alloys.

[0035] As mentioned above, the turbine components in the turbofan engine, such as Figure 1 As shown, it can be made of a titanium alloy. The titanium alloy contains 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen (e.g., up to 0.015wt% nitrogen); and the balance is titanium. In particular embodiments, the titanium alloy has a 0.2% yield strength of 1000 MPa or more (e.g., 1000 MPa to 1380.0 MPa), an ultimate tensile strength of 1060 MPa or more (e.g., 1060 MPa to 1450 MPa), a plastic elongation of 15.0% or more (e.g., 15.0% to 30.0%), ballistic impact resistance as measured by a crack length of 3.048 mm or less (e.g., 0 mm to 3.048 mm), an area reduction of 45% RA or more (e.g., 45% RA to 75% RA), or any combination of these properties.

[0036] Silicon (Si) is contained in the titanium alloy to increase strength. It has been found that less than 0.10wt% Si does not impart sufficient strength to the titanium alloy. In addition, it has been found that silicon greater than 0.30wt% results in poor ballistic impact resistance, poor plastic elongation, poor area reduction, or a combination thereof. In addition, it has been found that increasing the Si content beyond 0.30wt% may lead to silicon segregation problems during solidification of large diameter ingots necessary for large-scale production and manufacturing processes.

[0037] Iron (Fe) is contained in the titanium alloy to enhance high temperature strength and increase the temperature width of the α+β phase field, thereby improving the flexibility of the hot working process. It has been found that at least 0.20wt% of iron combined with 1.00wt% to 1.50wt% of molybdenum leads to a desired balance of strength and plastic elongation. However, during the solidification of large diameter ingots, Fe segregates strongly, and it is found that up to 0.70wt% of iron avoids production problems during large-scale production and manufacturing.

[0038] Molybdenum (Mo) is contained in titanium alloys to enhance high temperature strength and creep resistance, and to increase the temperature width of the α+β phase field, thereby increasing the flexibility of the hot working process. It has been found that at least 1.00wt% Mo combined with 0.20wt% to 0.70wt% Fe results in a desired balance of strength and plastic elongation. However, the presence of too much Mo in the titanium alloy may reduce the plastic elongation, area reduction rate and / or ballistic impact resistance of the titanium alloy. Therefore, it has been found that exceeding 1.50wt% will deteriorate the plastic elongation, area reduction rate and / or ballistic impact resistance of the titanium alloy to a degree beyond what is desired. An increase in the Mo content also leads to an increase in the density of the titanium alloy.

[0039] Nitrogen (N) is present in titanium alloys due to the inevitable pickup during the vacuum melting step in the production of titanium alloys. Nitrogen will increase the strength and hardness of titanium alloys. However, the presence of too much nitrogen in titanium alloys, such as nitrogen above 0.016wt% (e.g., nitrogen above 0.015wt%), leads to lower plastic elongation, lower area reduction rate and / or lower ballistic impact resistance.

[0040] Oxygen (O) is naturally present in titanium alloys due to the high oxidation rate of titanium and may be intentionally added to meet the desired chemical properties. However, the amount of oxygen present in the currently disclosed titanium alloys is minimized because it has been found that more than 0.21 wt% oxygen in the titanium alloy will result in reduced plastic elongation, area reduction and / or ballistic impact resistance.

[0041] Carbon (C) is naturally present in titanium alloys due to low levels of raw materials used in the formulation, and can be intentionally added to meet the desired chemical properties. A certain amount of C above 0.01 wt% is conducive to 0.2% yield strength and ultimate tensile strength without reducing plastic elongation, area reduction and / or ballistic impact resistance; however, the presence of more than 0.03 wt% of carbon in the alloy leads to reduced plastic elongation, area reduction and / or ballistic impact resistance.

[0042] In certain embodiments, the inclusion of other elements in the titanium alloy may be avoided to avoid undesirable properties. For example, the inclusion of certain elements may prevent large-scale use, such as in large-scale manufacturing processes for such turbine components.

[0043] Although copper (Cu) can improve the strength of titanium alloys, it has been found that the presence of copper can cause severe segregation during solidification of large diameter ingots and can cause large-scale production chemistry and microstructure control problems. Therefore, the presence of Cu in titanium alloys can form an inhomogeneous titanium alloy material that is not suitable for manufacturing turbine components with consistent composition within each component and across all components. Therefore, titanium alloys are substantially free of Cu to avoid these problems that would hinder the use of titanium alloys in large-scale manufacturing environments.

[0044] Although chromium (Cr) can increase the strength of titanium alloys, it has been found that the presence of chromium can cause segregation during solidification and can cause large-scale production chemistry and microstructure control problems. Therefore, the presence of chromium in the titanium alloy may form an inhomogeneous titanium alloy material that is not suitable for manufacturing turbine components with consistent composition within each component and in all components. Therefore, in certain embodiments, the titanium alloy is substantially free of chromium (e.g., no more than any residual amount of chromium present due to the presence of chromium in the titanium sponge, such as no more than 500wppm, such as no more than 200wppm) to avoid these problems that would hinder the use of titanium alloys in large-scale manufacturing environments.

[0045] Although tin (Sn) can improve the strength of the alloy, especially at high temperatures, it has been found that the presence of tin can lead to reduced plastic elongation, reduced area reduction, and reduced ballistic impact resistance. Therefore, in certain embodiments, the titanium alloy is substantially free of tin to avoid these problems.

[0046] Although nickel (Ni) can increase the strength of the alloy, it has been found that the presence of nickel can cause segregation during solidification and can cause large-scale production chemistry and microstructure control problems. Therefore, the presence of nickel in the titanium alloy may form an inhomogeneous titanium alloy material that is not suitable for manufacturing turbine components with consistent composition within each component and in all components. Therefore, in certain embodiments, the titanium alloy is substantially free of nickel (e.g., no more than any residual amount of nickel present due to the presence of nickel in the titanium sponge, such as no more than 500wppm, such as no more than 200wppm) to avoid these problems that would hinder the use of titanium alloys in large-scale manufacturing environments.

[0047] Although zirconium (Zr) can improve the strength of titanium alloys, especially at high temperatures, it has been found that the presence of zirconium and silicon in titanium alloys forms a mixed (TiZr) 6 Si 3 Silicide particles, which will quickly reduce plastic elongation, reduce area reduction, and reduce ballistic impact resistance. Therefore, in certain embodiments, the titanium alloy is substantially free of Zr to avoid these problems.

[0048] Although tungsten (W) can improve the strength and creep strength of titanium alloys, the inclusion of tungsten may result in an inhomogeneous alloy material due to its relatively high density compared to titanium. Therefore, in certain embodiments, the titanium alloy is substantially free of tungsten to avoid this problem.

[0049] In a specific embodiment, the titanium alloy described herein can be forged from a cylindrical billet into a shaped body closer to the final turbine component in one or more steps below the beta transformation temperature, which is the temperature when heated at which all low-temperature alpha close-packed hexagonal phases disappear and a high-temperature beta body-centered cubic phase exists. The forging temperature may be below the beta transformation temperature of the titanium alloy and may vary between 14°C and 83°C below the beta transformation temperature.

[0050] The forged body can be solution heat treated at a temperature closer to the β-transus temperature than the forging temperature to control the volume fraction of the primary α phase and the β phase. For example, the solution temperature can generally vary from 17°C to 69°C below the β-transus temperature, and the solution time should be at least 1 hour.

[0051] It is well known that increasing the cooling rate after solution heat treatment may result in an increase in the 0.2% yield strength and ultimate tensile strength. For the purposes of this application, all alloys were solution heat treated and cooled at a rate of about 208°C / min (corresponding to a cross-sectional size of about 80 mm in parts that were water quenched by solution heat treatment). Therefore, all tensile properties measured and reported here correspond to those expected in large cross-sectional size parts, on the order of 101.6 mm, which will be liquid quenched (e.g., water, oil, polymer, etc.) or gas cooled (e.g., air, helium, etc.) after solution heat treatment. It is well known that higher strength can be achieved by increasing the cooling rate after solution heat treatment. The post-solution cooling rate at any location in the heat treated part can be measured directly using embedded thermocouples, or estimated using a finite element model, or some combination of the two. The post-solution cooling rate can be measured and / or calculated between temperatures of about 28°C below the solution temperature and 83°C below the solution temperature.

[0052] After solution heat treatment and cooling, the part can be overaged at 537.8°C to 760°C for at least 1.5 hours (e.g., 2 hours) to minimize residual stresses generated by solution heat treatment and cooling while maintaining a balance between 0.2% yield strength, ultimate tensile strength, plastic elongation, area reduction, and ballistic impact resistance. Through these treatment methods, the desired properties of the titanium alloy can be achieved, such as 0.2% yield strength of more than 1000 MPa (e.g., 1000 MPa to 1380 MPa), ultimate tensile strength of more than 1060 MPa (e.g., 1060 MPa to 1450 MPa), plastic elongation of more than 15.0% (e.g., 15.0% to 30.0%), ballistic impact resistance measured by a crack length of less than 3.048 mm (e.g., 0 mm to 3.048 mm), area reduction of more than 45% RA (e.g., 45% RA to 75% RA), or any combination of these properties.

[0053] As noted above, the titanium alloys described herein may be used to form turbine components, such as for example turbofan engines. Figure 1 1 is a schematic diagram of an exemplary turbofan engine 10 having a central rotational axis 12. In an exemplary embodiment, the turbofan engine 10 includes an intake side 14 and an exhaust side 16. The turbofan engine 10 also includes a core gas turbine engine 18, which includes a high-pressure compressor 20, a combustor 22, and a high-pressure turbine 24. In addition, the turbofan engine 10 includes a low-pressure turbine 26 and a fan assembly 28, the low-pressure turbine 26 being axially disposed downstream of the core gas turbine engine 18, and the fan assembly 28 being axially disposed upstream of the core gas turbine engine 22. The fan assembly 28 includes an array of fan blades 30 extending radially outward from a rotor hub 32. In addition, the turbofan engine 10 includes a first rotor shaft 34 disposed between the fan assembly 28 and the low-pressure turbine 26, and a second rotor shaft 36 disposed between the high-pressure compressor 20 and the high-pressure turbine 24, such that the fan assembly 28, the high-pressure compressor 20, the high-pressure turbine 24, and the low-pressure turbine 26 are in series flow communication and coaxially aligned relative to the central rotational axis 12 of the turbofan engine 10.

[0054] During operation, air enters through the intake side 14 and flows through the fan assembly 28 to the high pressure compressor 20. The compressed air is delivered to the combustor 22. The airflow from the combustor 22 drives the high pressure turbine 24 and the low pressure turbine 26 before being discharged from the turbofan engine 10 through the exhaust side 16.

[0055] The high pressure compressor 20, the combustor 22, the high pressure turbine 24, and the low pressure turbine 26 each include at least one rotor assembly. The rotating or rotor assemblies are generally subject to different temperatures, depending on their relative axial positions within the turbofan engine 10. For example, in the exemplary embodiment, the turbofan engine 10 generally has a cooler operating temperature toward the front fan assembly 28 and a hotter operating temperature toward the rear high pressure compressor 20. Therefore, the rotor components within the high pressure compressor 20 are generally manufactured from materials that can withstand higher temperatures than the materials from which the rotor components of the fan assembly 28 are manufactured.

[0056] Although the turbofan engine 10 represents one member of the rotating machine category, other members include land-based gas turbines, turbojets, turboshaft engines, unducted engines, unguided fans, fixed-wing and propeller rotors, etc., as well as distributed propulsion devices such as distributed fans or pods, etc. The turbine components formed from the titanium alloys described herein can be in the form of rotating machine components for operating such rotating machines. For example, exemplary rotating machine components include disks, bladed disks, airfoils, blades, vanes, integral blade rotors, frames, fairings, seals, gearboxes, housings, brackets, shafts, etc.

[0057] Figure 2 An example of a turbine component that may be fabricated from a titanium alloy is shown, depicting an isometric view of a single-stage bladed disk 50, which may alternatively be referred to as an integral bladed rotor. The bladed disk 50 has a hub 52 that is oriented about a central rotation axis 12, referenced to Figure 1 The axis 12 of the turbofan engine 10. Extending generally radially from the hub 52 is an airfoil 60. Figure 1 In the high pressure compressor 20 of FIG. 5 , in order to optimize the performance parameters of the bladed disk, such as fatigue life, FOD resistance, and creep strength, a bimetallic bladed disk may be preferred, wherein the hub 52 and the airfoil 60 are different alloys. The airfoil 60 may be solid state welded to the hub 52 using a process such as translational friction welding or linear friction welding. Therefore, it may be desirable to select a material that provides excellent thick section properties for the hub 52 and provides excellent fatigue properties and FOD properties for the airfoil 60 in a relatively small cross-sectional size.

[0058] exist Figure 2 In the exemplary embodiment shown, the hub 52 is made of the titanium alloy described herein, and the airfoil 60 is made of a commercially available or conventional material having desirable fatigue life properties, such as Ti-64. After welding, the interface between the hub 52 and the airfoil 60 may be referred to as a weld or heat affected zone 70. In this zone 70, there is a mix of hub and airfoil alloys, as well as a wide range of microstructures. The mix of alloys and the range of microstructures may be detrimental to thick section fatigue, FOD, etc. in portions of the blade disk 50.

[0059] In another exemplary embodiment, the hub 52 and the airfoil 60 are both made of the same titanium alloy of the present disclosure, or of a separate exemplary titanium alloy of the present disclosure. In the case where the hub 52 and the airfoil 60 are the same titanium alloy, in the region 70, there is no mixing of the hub and airfoil alloys, but there is a wide range of microstructures. This range of microstructures may again compromise thick section fatigue, FOD, etc. of portions of the bladed disk 50.

[0060] In the high pressure compressor 20 shown in FIG1 , to optimize the mass of the rotating components (by eliminating bolted joints) and to utilize high temperature materials, adjacent stages of bladed disks may be inertia welded. Similar to the bimetallic hub / airfoil, it may be desirable to have a leading stage bladed disk made of a first material and a trailing stage bladed disk made of a second material. Figure 3 As shown, the front bladed disk stage 80 may be made of an example titanium alloy of the present disclosure, and the aft bladed disk stage 90 may be made of a conventional material, such as Ti- 17. Again, there is a weld zone or heat affected zone 70, and there is a mix of the front bladed disk and aft bladed disk alloys, as well as a wide range of microstructures in the region 70, indicating an area of ​​reduced material properties.

[0061] In other exemplary embodiments, the adjacent front-stage blisks 80 and rear-stage blisks 90 are both made of the same titanium alloy of the present disclosure, or may be made of separate exemplary titanium alloys of the present disclosure.

[0062] In addition, for Figure 2 and Figure 3 In the illustrated embodiments, any of the exemplary titanium alloys of the present disclosure may be used alone, or in combination with commercially available alloys, for one or more of the airfoil 60, the hub 52, the blade disk 50, the front-stage blade disk 80, or the rear-stage blade disk 90. Figure 3 Two stages are described, but more than two stages of bladed disks are contemplated.

[0063] Although materials may be selected based solely on these properties, consideration should be given to recovering material properties lost due to the thermal environment caused by welding in translational friction welding or linear friction welding through post-treatment (e.g., furnace heat treatment). As will be discussed below, the titanium alloy of the present disclosure pairs well with commercially available titanium alloys, allowing manufacturers to fully exploit the benefits of this bimetallic material property by, for example, better matching heat treatment temperatures and treatments between the hub 52 material and the airfoil 60 material and between the materials of adjacent stage blade disks 80 and 90. These benefits can also be achieved when the titanium alloy of the present disclosure is welded to itself, rather than just to commercially available titanium alloys. In the case of translational friction welded bimetallic blade disks, using the titanium alloy of the present disclosure as the hub instead of beta-treated Ti-17 or beta-treated Ti-6246, and using Ti-64 as the airfoil will result in better matching of flow stresses and microstructures between the titanium alloy of the hub and the Ti-64 alloy airfoil. This can result in a lower tendency for solid-state welds to form defects during or after welding.

[0064] Example components may be of thick sections, cast and forged, or aerospace structural castings, etc.

[0065] Example

[0066] Exemplary alloys (E-1 to E-20) were made according to the chemistries shown in Table 1. These exemplary alloys were formed by an open die forging process designed to replicate a typical production billet conversion process; the as-cast ingot was first hot worked above the beta transus temperature, followed by sub-transus temperature hot working, resulting in beta recrystallization, followed by reheating the material above the beta transus temperature and further hot working, followed by a water quench. Finally, the material was reheated to below the beta transus temperature and hot worked to final diameter. All hot working was done using open die forging, as used in large-scale production ingot to billet processing, in order to make the microstructure and texture of the sub-size material representative of the larger production size material.

[0067] The comparative alloys are described below and shown in Tables 2, 3A and 3B. The alloys of Tables 1, 2, 3A and 3B were cooled at 208°C / min from α+β solution heat treatment. These alloys were measured at 23°C according to ASTM E8 / E8M to determine the 0.2% yield strength YS, UTS, plastic elongation (expressed in %) and area reduction (expressed in %).

[0068] The 0.2% YS data at 23°C for the alloys shown in Table 1 were entered into a multiple linear regression statistical model using a commercially available statistical analysis package (MiniTab V.20.2). The following elements were determined to be statistically significant using the p-test, with a confidence level a greater than 95% for each element: Al, O, Fe, Si, Mo. The yield strength prediction model is shown in Equation 1:

[0069] Equation 1

[0070] 0.2% YS(MPa)=469.3+48.8×Al(wt%)+748×O(wt%)+96.1×Fe(wt%)+

[0071] 188×Si(wt%)+57.7×Mo(wt%)

[0072] For high strength titanium alloy applications, it is desirable that the candidate alloy has 0.2% YS ≥ 1000 MPa at 23°C.

[0073] The UTS data at 23°C for the alloys shown in Table 1 were input into a multiple linear regression statistical model using a commercially available statistical analysis package (MiniTab V.20.2). The following elements were determined to be statistically significant using the p-test, with the confidence level a for each element being greater than 95%: Al, O, Fe, Si, Mo. The ultimate tensile strength prediction model is shown in Equation 2:

[0074] Equation 2

[0075] UTS(MPa)=612.1+39.2×Al(wt%)+666×O(wt%)+74.6×Fe(wt%)+

[0076] 202×Si(wt%)+41.6Mo(wt%))

[0077] For high strength titanium alloy applications, it is desirable that the candidate alloy has a UTS ≥ 1060 MPa at 23°C.

[0078] Using a commercially available statistical analysis package (MiniTab V.20.2), the % plastic elongation (% EL) at 23°C of the alloys shown in Table 1 was entered into a multivariate linear regression statistical model. Note that the Log (10) transformation of the % plastic elongation value was used for statistical analysis in accordance with standard practice for log-normally distributed data (J Chen, Z Wang et al., Int. J. Plast. 152 (2022) 103260). The following elements were determined to be statistically significant using the p-test, with a confidence level a>95% for the statistical significance of each element: Fe, Si, Mo. The yield strength prediction model is shown in Equation 3:

[0079] Equation 3

[0080] EL(%)=10^(1.149+0.211×Fe(wt%)–0.514×Si(wt%)+0.076×Mo(wt%))

[0081] For high strength titanium alloy applications, it is desirable that the candidate alloy has a plastic elongation % at 23°C ≥ 15.0%.

[0082] Using a commercially available statistical analysis package (MiniTab V20.2), the area reduction % (%RA) at 23°C of the alloys shown in Table 1 was entered into a multiple linear regression statistical model. Note that the Log(10) transformation of the area reduction % values ​​was used for statistical analysis in accordance with standard practices for log-normally distributed data (J Chen, ZWang et al., Int. J. Plast. 152 (2022) 103260). The following elements were determined to be statistically significant using the p-test, with a confidence level a>95% for the statistical significance of each element: Fe, Si, Mo. The yield strength prediction model is shown in Equation 4:

[0083] Equation 4

[0084] RA(%)=10^(1.560+0.195×Fe(wt%)–0.663×Si(wt%)+0.139×Mo(wt%))

[0085] For high strength titanium alloy applications, it is desirable that the candidate alloy has a % reduction in area at 23°C ≥ 45.0%.

[0086] In certain embodiments, it is desirable for a high strength titanium alloy to have both high strength (≥ 1000 MPa at 0.2% YS, according to Equation 1) and high plastic elongation % (≥ 15.0%, according to Equation 3).

[0087] Comparative alloys (C-1 to C-20) were also made according to the chemical compositions shown in Table 2. These comparative alloys were open die forged like the exemplary alloys of Table 1. The properties of each of the alloys of Table 2 were measured at 23° C. according to ASTM E8 / E8M. As shown in the results of Table 2, these comparative alloys do not meet the specifications of the desired titanium alloys.

[0088] Comparative alloys (C-21 to C-50) were made according to the chemical compositions shown in Table 3A, and comparative alloys (C-51 to C-66) were made according to the chemical compositions shown in Table 3B. As shown in the results of Tables 3A and 3B, these comparative alloys did not meet the specifications of the desired titanium alloys.

[0089] Alloy data from U.S. Patent Publication No. 2017 / 0268091 is reproduced in Table 4 as comparative alloys (Comp-A to Comp-M (Comp-A to Comp-M)). The alloys of Table 4 were cast into ingots and then extruded to final size in the α / β phase field without following the usual open die forging billet process. Due to the texture differences caused by the extrusion process, the extrusion process may result in different combinations of 0.2% yield strength, ultimate tensile strength, plastic elongation % and area reduction % . This process is completely different from the process used in large-scale manufacturing production. Therefore, although the comparative-G alloy meets some of the target alloy properties, the elongation is predicted to be lower for alloys that will be processed according to the open die forging process (such as used for the exemplary alloys of Table 1). Therefore, it is believed that the comparative-G alloy will result in an alloy with a lower elongation than shown in Table 4 during large-scale processing. Although the comparative-J alloy meets some of the target alloy properties, the presence of copper causes problems for the comparative-J alloy in large-scale use. That is, the presence of copper will lead to severe segregation during solidification of large diameter ingots and will cause large-scale production chemistry and microstructure control problems.

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] Other aspects are provided by the following subjects:

[0096] A turbine component comprising a titanium alloy, wherein the titanium alloy comprises: 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen (e.g., up to 0.015wt% nitrogen); and the balance is titanium, wherein the titanium alloy is substantially free of copper.

[0097] A turbine component comprising a titanium alloy, wherein the titanium alloy comprises: 5.50 wt% to 6.90 wt% aluminum; 3.50 wt% to 4.50 wt% vanadium; 0.01 wt% to 0.03 wt% carbon; 0.20 wt% to 0.70 wt% iron; 1.00 wt% to 1.50 wt% molybdenum; 0.10 wt% to 0.30 wt% silicon; up to 0.21 wt% oxygen; up to 0.016 wt% nitrogen (e.g., up to 0.015 wt% nitrogen); and the balance is titanium, wherein the amounts of Al, O, Fe, Si, and Mo present are Resulting in a 0.2% yield strength at 23°C of ≥1000 MPa as predicted by the following formula: 469.3+48.8×Al(wt%)+748×O(wt%)+96.1×Fe(wt%)+188×Si(wt%)+57.7×Mo(wt%), and / or wherein the presence of Fe, Si and Mo results in a plastic elongation % at 23°C of ≥15.0% as predicted by the following formula: 10^(1.149+0.211×Fe(wt%)–0.514×Si(wt%)+0.076×Mo(wt%)).

[0098] A turbine component as described in any preceding clause, wherein the titanium alloy is substantially free of copper.

[0099] A turbine component as claimed in any preceding clause, wherein the titanium alloy has a 0.2% yield strength of above 1000 MPa.

[0100] A turbine component according to any preceding clause, wherein the titanium alloy has a 0.2% yield strength of 1000 MPa to 1380 MPa.

[0101] A turbine component as described in any preceding clause, wherein the titanium alloy has an ultimate tensile strength of greater than 1060 MPa.

[0102] A turbine component as described in any preceding clause, wherein the titanium alloy has an ultimate tensile strength of 1060 MPa to 1450 MPa.

[0103] A turbine component as described in any preceding clause, wherein the titanium alloy has a plastic elongation greater than 15.0%.

[0104] A turbine component as described in any preceding clause, wherein the titanium alloy has a plastic elongation of 15.0% to 30.0%.

[0105] A turbine component as described in any of the preceding clauses, characterized in that the titanium alloy has a ballistic impact resistance measured by a crack length of less than 3.048 mm.

[0106] A turbine component as claimed in any preceding clause, wherein the titanium alloy has a ballistic impact resistance as measured by a crack length of 0 mm to 3.048 mm.

[0107] A turbine component as claimed in any preceding clause, wherein the turbine component has an area reduction of greater than 45% RA.

[0108] A turbine component as claimed in any preceding clause, wherein the turbine component has a reduced area of ​​45% RA to 75% RA.

[0109] A turbine component as described in any of the preceding clauses, wherein the titanium alloy has a 0.2% yield strength of 1000 MPa or more, an ultimate tensile strength of 1060 MPa or more, a plastic elongation of 15.0% or more, and an area reduction of 45% RA or more.

[0110] A turbine component as described in any of the preceding clauses, wherein the titanium alloy has a 0.2% yield strength of 1000 MPa to 1380 MPa, an ultimate tensile strength of 1060 MPa to 1450 MPa, a ductility of 15.0% to 30.0% and an area reduction of 45% RA to 75% RA.

[0111] A turbine component as described in any preceding clause, wherein the titanium alloy is substantially free of chromium.

[0112] A turbine component as claimed in any preceding clause, wherein the titanium alloy is substantially free of tin.

[0113] A turbine component as described in any preceding clause, wherein the titanium alloy is substantially free of nickel.

[0114] A turbine component as claimed in any preceding clause, wherein the titanium alloy is substantially free of zirconium.

[0115] A turbine component as claimed in any preceding clause, wherein the titanium alloy is substantially free of tungsten.

[0116] A turbine component as described in any preceding clause, wherein the titanium alloy contains substantially no other elements.

[0117] A turbine component as described in any of the preceding clauses, wherein the amounts of Al, O, Fe, Si and Mo present result in a 0.2% yield strength at 23°C predicted by the following formula: 469.3+48.8×Al(wt%)+748×O(wt%)+96.1×Fe(wt%)+188×Si(wt%)+57.7×Mo(wt%).

[0118] A turbine component as described in any of the preceding clauses, wherein the amounts of Fe, Si and Mo present result in a plastic elongation % at 23°C predicted according to the following formula ≥ 15.0%: 10^(1.149+0.211×Fe(wt%)−0.514×Si(wt%)+0.076×Mo(wt%)).

[0119] A turbine component as described in any of the preceding clauses, wherein the amounts of Al, O, Fe, Si and Mo present result in a 0.2% yield strength at 23°C predicted by the following formula of ≥1000 MPa: 469.3+48.8×Al(wt%)+748×O(wt%)+96.1×Fe(wt%)+188×Si(wt%)+57.7×Mo(wt%), wherein the amounts of Fe, Si and Mo present result in a plastic elongation % at 23°C predicted by the following formula of ≥15.0%: 10^(1.149+0.211×Fe(wt%)–0.514×Si(wt%)+0.076×Mo(wt%)).

[0120] A turbine component as claimed in any preceding clause, wherein the titanium alloy comprises 3.80 wt % to 4.43 wt % vanadium.

[0121] A turbine component as claimed in any preceding clause, wherein the titanium alloy comprises 0.45 wt % to 0.57 wt % iron.

[0122] A turbine component as claimed in any preceding clause, wherein the titanium alloy comprises 0.14 wt % to 0.28 wt % silicon.

[0123] A turbine component as described in any of the preceding clauses, wherein the titanium alloy consists essentially of the following components: 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen (e.g., up to 0.015wt% nitrogen); and the balance is titanium.

[0124] A turbine component as described in any of the preceding clauses, wherein the titanium alloy consists of the following composition:

[0125] 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen (e.g., up to 0.015wt% nitrogen); and the balance is titanium.

[0126] A turbine component comprising a titanium alloy, wherein the titanium alloy consists essentially of: 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen (e.g., up to 0.015wt% nitrogen); and the balance is titanium.

[0127] A turbine component comprising a titanium alloy, wherein the titanium alloy consists of the following components: 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen (e.g., up to 0.015wt% nitrogen); and the balance is titanium.

[0128] A turbine component as claimed in any preceding clause, wherein the titanium alloy has a 0.2% yield strength of above 1000 MPa.

[0129] A turbine component as claimed in any preceding clause, wherein the titanium alloy has a 0.2% yield strength of 1000 MPa to 1380 MPa.

[0130] A turbine component as described in any of the preceding clauses, wherein the titanium alloy has an ultimate tensile strength of 1060 MPa or more.

[0131] A turbine component as described in any preceding clause, wherein the titanium alloy has an ultimate tensile strength of 1060 MPa to 1450 MPa.

[0132] A turbine component as described in any preceding clause, wherein the titanium alloy has a plastic elongation of greater than 15.0%.

[0133] A turbine component as described in any preceding clause, wherein the titanium alloy has a plastic elongation of 15.0% to 30.0%.

[0134] A turbine component as described in any preceding clause, wherein the titanium alloy has a ballistic impact resistance as measured by a crack length of less than 3.048 mm.

[0135] A turbine component as described in any preceding clause, wherein the titanium alloy has a ballistic impact resistance measured by a crack length of 0 mm to 3.048 mm.

[0136] A turbine component as claimed in any preceding clause, wherein the turbine component has an area reduction of greater than 45% RA.

[0137] A turbine component as claimed in any preceding clause, wherein the turbine component has a reduced area of ​​45% RA to 75% RA.

[0138] A turbine component as described in any of the preceding clauses, wherein the titanium alloy has a 0.2% yield strength of 1000 MPa or more, an ultimate tensile strength of 1060 MPa or more, a plastic elongation of 15.0% or more, a crack length of 3.048 mm or less, and an area reduction of 45% RA or more.

[0139] [A turbine component as described in any of the preceding clauses, wherein the titanium alloy has a 0.2% yield strength of 1000 MPa to 1380 MPa, an ultimate tensile strength of 1060 MPa to 1450 MPa, a ductility of 15.0% to 30.0%, ballistic impact resistance measured by a crack length of 0 to 3.048 mm, and an area reduction of 45% RA to 75% RA.

[0140] A method of forming a turbine component as described in any preceding clause.

[0141] A method for forming a turbine component, the method comprising: forging a titanium alloy into a turbine component, wherein the titanium alloy comprises: 5.50wt% to 6.90wt% aluminum; 3.50wt% to 4.50wt% vanadium; 0.01wt% to 0.03wt% carbon; 0.20wt% to 0.70wt% iron; 1.00wt% to 1.50wt% molybdenum; 0.10wt% to 0.30wt% silicon; up to 0.21wt% oxygen; up to 0.016wt% nitrogen (e.g., up to 0.015wt% nitrogen); and the balance is titanium, wherein the titanium alloy is substantially free of copper.

[0142] A method of forming a turbine component, the method comprising: forging a titanium alloy into a turbine component, wherein the titanium alloy comprises: 5.50 wt% to 6.90 wt% aluminum; 3.50 wt% to 4.50 wt% vanadium; 0.01 wt% to 0.03 wt% carbon; 0.20 wt% to 0.70 wt% iron; 1.00 wt% to 1.50 wt% molybdenum; 0.10 wt% to 0.30 wt% silicon; up to 0.21 wt% oxygen; up to 0.016 wt% nitrogen (e.g., up to 0.015 wt% nitrogen); and the balance is titanium, wherein Al, O, Fe The presence of Fe, Si and Mo results in a 0.2% yield strength at 23°C of ≥1000 MPa as predicted by the following formula: 469.3+48.8×Al(wt%)+748×O(wt%)+96.1×Fe(wt%)+188×Si(wt%)+57.7×Mo(wt%), and / or the presence of Fe, Si and Mo results in a plastic elongation at 23°C of ≥15.0% as predicted by the following formula: 10^(1.149+0.211×Fe(wt%)–0.514×Si(wt%)+0.076×Mo(wt%)).

[0143] A method as described in any of the preceding clauses, wherein forging the titanium alloy into a turbine component includes: forging the titanium alloy at a forging temperature below the beta transus temperature of the titanium alloy.

[0144] A method as described in any of the preceding clauses, wherein the method includes: heat treating the titanium alloy.

[0145] A method as described in any of the preceding clauses, wherein the method includes: solution heat treating the titanium alloy at a heat treatment temperature below the beta transus temperature of the titanium alloy.

[0146] A method as described in any of the preceding clauses, wherein the heat treatment temperature is higher than the forging temperature, and wherein the titanium alloy is maintained at the heat treatment temperature for at least 1 hour.

[0147] A method as described in any of the preceding clauses, wherein the method includes: cooling the titanium alloy after heat treating the titanium alloy to form a turbine component.

[0148] A method as described in any of the preceding clauses, wherein cooling the titanium alloy is performed at a cooling rate of 208°C / min starting from the heat treatment temperature.

[0149] A method as described in any of the preceding clauses, wherein the method further comprises: after solution heat treatment and cooling, heating the titanium alloy to an overaging heat treatment temperature of 538°C to 760°C for at least 1.5 hours.

[0150] A method as in any preceding clause, wherein the titanium alloy has a 0.2% yield strength above 1000 MPa.

[0151] A method as described in any of the preceding clauses, wherein the titanium alloy has an ultimate tensile strength of 1060 MPa or more.

[0152] A method as described in any of the preceding clauses, wherein the titanium alloy has a plastic elongation greater than 15.0%.

[0153] A method as in any preceding clause, wherein the titanium alloy has ballistic impact resistance as measured by a crack length of less than 3.048 mm.

[0154] A method as described in any of the preceding clauses, wherein the titanium alloy has an area reduction of greater than 45% RA.

[0155] A titanium alloy formed by the method of any preceding clause.

[0156] This written description uses examples to disclose the present disclosure, including the best mode, and to enable any person skilled in the art to practice the present disclosure, including making and using any device or system and performing any combined method. The patentable scope of the present disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. If these other examples include structural elements that do not differ from the literal language of the claims, or if these other examples include equivalent structural elements that do not differ substantially from the literal language of the claims, these other examples are intended to be within the scope of the claims.

Claims

1. Turbine components, including titanium alloys, It is characterized in that The titanium alloy comprises: 5.50 to 6.90 wt % aluminum; 3.50 to 4.50 wt% vanadium; 0.01 wt% to 0.03 wt% carbon; 0.20 to 0.70 wt % iron; 1.00 wt % to 1.50 wt % of molybdenum; 0.10 wt % to 0.30 wt % silicon; Up to 0.21 wt% oxygen; Up to 0.016 wt% nitrogen; and The balance is titanium, The titanium alloy is substantially free of copper.

2. Turbine components, including titanium alloys, It is characterized in that The titanium alloy comprises: 5.50 to 6.90 wt % aluminum; 3.50 to 4.50 wt% vanadium; 0.01 wt% to 0.03 wt% carbon; 0.20 to 0.70 wt % iron; 1.00 wt % to 1.50 wt % of molybdenum; 0.10 wt % to 0.30 wt % silicon; Up to 0.21 wt% oxygen; Up to 0.016 wt% nitrogen; and The balance is titanium, wherein the amount of Al, O, Fe, Si, and Mo present results in a 0.2% yield strength at 23°C of ≥ 1000 MPa as predicted by the following formula: 469.3 + 48.8 × Al (wt%) + 748 × O (wt%) + 96.1 × Fe (wt%) + 188 × Si (wt%) + 57.7 × Mo (wt%), or The presence of Fe, Si and Mo results in a plastic elongation %≥15.0% at 23°C predicted by the following formula: 10^(1.149+0.211×Fe(wt%)–0.514×Si(wt%)+0.076×Mo(wt%)).

3. A turbine component according to any one of the preceding claims, It is characterized in that The titanium alloy is substantially free of copper.

4. A turbine component according to any one of the preceding claims, It is characterized in that The titanium alloy has a 0.2% yield strength of 1000 MPa or more.

5. Turbine component according to any one of the preceding claims, It is characterized in that The titanium alloy has a 0.2% yield strength of 1000 MPa to 1380 MPa.

6. A turbine component according to any one of the preceding claims, It is characterized in that The titanium alloy has an ultimate tensile strength of more than 1060 MPa.

7. A turbine component according to any one of the preceding claims, It is characterized in that The titanium alloy has an ultimate tensile strength of 1060 MPa to 1450 MPa.

8. A turbine component according to any one of the preceding claims, It is characterized in that The titanium alloy has a plastic elongation of greater than 15.0%.

9. A turbine component according to any one of the preceding claims, It is characterized in that The titanium alloy has a plastic elongation of 15.0% to 30.0%.

10. A turbine component according to any one of the preceding claims, It is characterized in that The titanium alloy has ballistic impact resistance as measured by a crack length of less than 3.048 mm.

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