RU2570858C2 - Alloy with ion-bombarded surface for protection against ambient effects - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to application of coating on substrate of heat-resistant nickel alloy and to article of said heat-resistant nickel alloy. Claimed article comprises the nickel allot substrate and modified underlying area and bulky area. The former contains the first composition while the latter includes the second composition other than the first one. Said modified underlying area includes at least one of reactive element or noble metal and features the depth smaller than approx 0.3 mcm measured in direction, on fact, perpendicular to substrate surface. Said modified underlying area is produced by deposition of the layer including at least one of reactive element or noble metal on substrate surface and introduction of said one of reactive element or noble metal in modified underlying area by ion bombardment.

EFFECT: production of heat-resistant nickel alloy article.

20 cl, 9 dwg

Description

FIELD OF TECHNOLOGY

[0001] The invention relates to alloys and coatings for alloys intended for use in high temperature mechanical systems.

BACKGROUND OF THE INVENTION

[0002] Parts of high temperature mechanical systems, such as, for example, gas turbine engines, must operate in harsh environments. For example, working and guide vanes, shrouds and retaining shelves of feather blades of high pressure turbines are directly affected by gases flowing in the hot path in commercial aircraft engines and usually experience temperatures on the metal surface of about 800 ° C, with short-term peaks up to 1100 ° C. The rim of the turbine disk (impeller) may be exposed to high temperatures between 600 ° C and 750 ° C. In some cases, the gases flowing in the hot duct may include oxidizing and / or corrosive chemicals, such as oxygen, sulfur, or the like, to which the rim of the turbine disk may be exposed. The high temperatures to which the rim is exposed can contribute to oxidation or corrosion when exposed to oxidizing and / or corrosive chemicals on the rim, which can affect the chemical and mechanical properties of the rim.

SUMMARY OF THE INVENTION

[0003] In general, the invention is directed to methods for forming a modified surface and / or subsurface region in an alloy part and to alloy parts that include a modified surface and / or subsurface region. In some examples, the alloy may be a nickel disk alloy, such as a γ-Ni + γ'-Ni ₃ Al alloy. In some examples, the alloy may be molded into a part of a gas turbine engine, such as a turbine disk. The modified surface and / or subsurface region may be formed by depositing a layer that includes at least one element on the surface of the alloy and bombarding the layer with inert ions using ion bombardment to introduce the element in the layer into the surface and / or subsurface region of the alloy.

[0004] In one aspect, the invention is directed to a method comprising depositing a plurality of atoms into a layer on a surface of a substrate that includes a nickel alloy. According to this aspect of the invention, the plurality of atoms includes at least one of a reactive element such as yttrium (Y), hafnium (Hf), zirconium (Zr), lanthanum (La), cerium (Ce), silicon (Si) or chromium (Cr ); or a noble metal such as platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os), gold (Au) or silver (Ag). The method may further include bombarding the layer with inert ions to introduce (implant) at least some of the many atoms into the subsurface region of the substrate within about 0.3 micrometers from the surface.

[0005] In yet another aspect, the invention is directed to an article that includes a substrate containing a nickel alloy. According to this aspect of the invention, the substrate may include a modified subsurface region and a volume region. The modified subsurface region may include a first composition, and the volume region may include a second composition different from the first composition. In some examples, the modified subsurface region includes at least one of a reactive element or a noble metal. In addition, the modified subsurface region may include a thickness of less than about 0.3 micrometers, measured in a direction substantially normal to the surface of the substrate.

[0006] Details of one or more examples are set forth below in the accompanying drawings and in the following description. Other features, objects, and advantages of the invention will be apparent from the description and drawings, as well as from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a conceptual sectional view that illustrates an exemplary alloy member.

[0008] FIG. 2 is a flowchart that illustrates one exemplary method of forming a modified subsurface region in an alloy substrate using ion bombardment.

[0009] FIG. 3A is a conceptual cross-sectional view that illustrates an exemplary alloy substrate and a plurality of atoms deposited on the surface of an alloy substrate.

[0010] Fig. 3B is a conceptual cross-sectional view that illustrates an exemplary alloy substrate that includes a modified subsurface region.

[0011] FIG. 4 is a flowchart that illustrates an example method of forming a modified subsurface region in an alloy substrate using ion bombardment.

[0012] FIG. 5A is a conceptual sectional view that illustrates an exemplary alloy substrate and two layers, each of which includes a plurality of atoms deposited on the surface of the alloy substrate.

[0013] FIG. 5B is a conceptual cross-sectional view that illustrates an example alloy substrate that includes a modified subsurface region.

[0014] FIG. 6 is a flowchart that illustrates an example method of forming a modified subsurface region in an alloy substrate using ion bombardment.

[0015] FIG. 7A is a conceptual cross-sectional view that illustrates an exemplary alloy substrate and a layer that includes a plurality of atoms deposited on the surface of the alloy substrate.

[0016] FIG. 7B is a conceptual sectional view that illustrates an exemplary alloy substrate that includes a modified subsurface region.

[0017] FIG. 7C is a conceptual sectional view that illustrates an exemplary alloy substrate and a layer that includes a plurality of atoms deposited on the surface of an alloy substrate over a modified subsurface region.

[0018] FIG. 7D is a conceptual cross-sectional view that illustrates an exemplary alloy substrate that includes a modified subsurface region.

[0019] FIG. 8 is a flowchart that illustrates an exemplary method of heat treating an alloy substrate to remove substantially all of the tertiary precipitated γ′-Ni ₃ Al phase from the alloy substrate.

[0020] FIG. 9 is a time-temperature graph that illustrates an exemplary heat treatment to which an alloy substrate can be subjected.

DETAILED DESCRIPTION OF THE INVENTION

[0021] In general, the invention is directed to methods for forming a modified surface and / or subsurface region in an article that includes a nickel alloy, and to articles that include such a modified surface and / or subsurface region. In some examples, the article may include a turbine disk. The modified surface and / or subsurface region may be formed first by depositing at least one element on a substrate surface. In some examples, this layer can be formed on a part of the substrate, leaving the other part of the substrate uncoated. In other examples, a layer can be formed on almost all surfaces of the substrate. A layer may include many atoms, and this many atoms may include a single element or a mixture of at least two elements. The element or elements may be selected to protect the product from oxidation and / or corrosion. For example, the elements may be selected from a reactive element or a noble metal.

[0022] An element or elements can be deposited to a thickness (measured in a direction substantially normal to the surface of the substrate) or a coating density (measured, for example, in grams of material per square centimeter of surface area (g / cm ² )), which results in a given composition in the modified subsurface region after introducing the element into the modified subsurface region.

[0023] After the layer has been deposited on the surface of the substrate, the layer can be bombarded with inert (non-reactive) ions such as xenon (Xe), helium (He), neon (Ne), argon (Ar), krypton (Kr) or radon (Rn). Ion bombardment can cause atoms in the layer to be introduced into the subsurface region. In some examples, ion bombardment and introduction of an element into a modified subsurface region may have little effect on the phase composition and / or microstructure of the subsurface region. For example, the subsurface region may include the phase composition of γ-Ni + γ'-Ni ₃ Al before introducing the element into the subsurface region and may also include the phase composition of γ-Ni + γ'-Ni ₃ Al after introducing the element into the subsurface region to form a modified subsurface area. In some examples, introducing an element into the subsurface region can also create residual stress in the subsurface region.

[0024] FIG. 1 is a conceptual view illustrating a cross section of one exemplary alloy part. In the illustrated example, the alloy part includes a gas turbine engine disk 10 used in a gas turbine engine. The gas turbine engine disk 10 includes a rim part 12, a hub part 14 and a part 16 with a drilled hole. In various examples, the gas turbine engine disk 10 may be a low, medium and high pressure compressor disk (LPC disk, IPC disk or HPC disk), low, medium and high pressure turbine disk (LPT disk, IPT disk or HPT disk) or a fan disk .

[0025] Although the following description will be directed mainly to a gas turbine engine disk 10 made of a γ-Ni + γ'-Ni ₃ Al alloy, in other examples, the alloy part may contain a different article or part other than the gas turbine engine disk 10, or may contain a different alloy. For example, the alloy part may be another part of a high-temperature mechanical system, such as a turbine blade or shaft for an aircraft engine, or may include another alloy product, which may benefit from a modified subsurface region. In addition, the methods described herein can be applied to other alloys, such as, for example, steel, aluminum alloys, cobalt alloys, titanium alloys, or the like. In some examples, the part may include two or more alloys interconnected, for example, a twin-alloy disk of a gas turbine engine.

[0026] When used in a gas turbine engine, the rim portion 12 of the disk 10 of the gas turbine engine may experience other operating conditions than the part 16 with the drilled hole of the disk 10 of the gas turbine engine. For example, the drilled hole portion 16 may be substantially isolated from the gases passing through the gas turbine engine, while the rim portion 12 may be exposed to these gases. As a consequence, the rim portion 12 may be exposed to higher temperatures and / or a more corrosive and / or oxidizing environment than the drilled hole portion 16. Accordingly, various mechanical and / or chemical properties may be useful for the drilled hole portion 16 and the rim portion 12, including properties along the surface and / or subsurface regions of the drilled hole portion 16 and the rim portion 12. For example, the drilled hole portion 16 having high tensile strength and high fatigue strength at lower temperatures may be useful, while improved creep resistance at higher Temperature, improved damage tolerance and improved fatigue resistance excerpt. Additionally or alternatively to the rim portion 12, a coating or surface area may be useful which (s) protects the rim portion 12 from environmental influences, for example, from corrosion and / or oxidation, while the bore portion 16 can be substantially insulated from hot gases and will not receive any benefit from the coating or surface area, which provide protection from environmental influences.

[0027] The chemical and mechanical properties of the rim part 12 and part 16 with the drilled hole may be affected by the chemical composition or metallographic structure, phase composition and / or microstructure of the corresponding part 12 or 16. The disk 10 of the gas turbine engine can be made of a wide range of alloys, including, for example, a heat-resistant alloy (superalloy) based on Ni. In some examples, the gas turbine engine disk 10 may be made of a heat-resistant Ni-based alloy having a phase composition of γ-Ni + γ'-Ni ₃ Al. In such examples, γ-Ni may be a continuous phase, for example, a matrix, and γ'-Ni ₃ Al may be a dispersed phase, for example, a precipitated phase. The γ'-Ni ₃ Al phase can be released into distinct, almost uniform domains within the γ-Ni matrix phase.

[0028] In some examples, the domains of the precipitated phase of γ'-Ni ₃ Al can be classified into domains of the primary precipitate, domains of the secondary precipitate, domains of the tertiary precipitate, or a combination thereof. The name “primary”, “secondary” or “tertiary” may refer to the way in which the domains of the precipitated γ'-Ni ₃ Al phase were formed, or to how the domains of the precipitated phase react to heat treatment. For example, the domains of the primary precipitated γ'-Ni ₃ Al phase may remain practically undissolved and may even become larger when the alloy is subjected to heat treatment below the phase transition temperature of the alloy. In some examples, the volume fraction of the domains of the primary precipitated γ'-Ni ₃ Al phase is determined by the temperature at which the heat treatment is performed, and the size of the domains of the primary precipitated γ'-Ni ₃ Al phase is determined by the duration of the heat treatment. On the contrary, the domains of the secondary precipitated γ'-Ni ₃ Al phase practically dissolve in the matrix phase, when the alloy is subjected to heat treatment above the lower threshold temperature and below the phase transition temperature of the alloy. The domains of the secondary precipitated γ'-Ni ₃ Al phase are formed during cooling of the alloy from relatively high temperatures. The domains of the tertiary precipitated phase γ'-Ni ₃ Al can also dissolve in the matrix phase, when the alloy is subjected to heat treatment above the lower threshold temperature and below the phase transition temperature of the alloy. The domains of the tertiary precipitated phase γ'-Ni ₃ Al can be formed during cooling of the alloy at relatively lower temperatures. In addition, the domains of the tertiary precipitated phase of γ'-Ni ₃ Al may become larger during aging, while the domains of the primary and secondary precipitated phases of γ'-Ni ₃ Al may be relatively unaffected by aging.

[0029] In some examples, the domains of the precipitated phase of γ'-Ni ₃ Al can also be classified based on the average diameter of the domains of the precipitated phase. For example, the domains of the tertiary precipitated phase γ'-Ni ₃ Al may have an average diameter between about 10 nanometers (nm) and about 50 nm (about 0.01 micrometers (microns) and about 0.05 microns), and the domains of the secondary precipitated phase γ '-Ni ₃ Al may have an average diameter between about 100 nm and about 300 nm (about 0.1 μm and about 0.3 μm). The domains of the primary precipitated phase γ′-Ni ₃ Al may have an average diameter between about 1 μm and about 3 μm.

[0030] In some examples, the volume fraction of the domains of the precipitated γ'-Ni ₃ Al phase and the type of domains of the precipitated γ'-Ni ₃ Al phase (eg, primary, secondary, tertiary) can affect the properties of the disk 10 of the gas turbine engine, such as for example, tensile strength, fatigue strength, creep resistance, damage resistance or endurance fatigue resistance.

[0031] The specific chemical composition of the alloy can also affect the properties of the disk 10 of the gas turbine engine, even within a single phase composition. For example, the relative amounts of elements in the alloy can affect the mechanical properties of the alloy, such as tensile strength, fatigue strength, creep resistance, damage resistance or endurance fatigue resistance. Similarly, the relative amounts of elements in the alloy can affect the chemical properties of the alloy, such as oxidation resistance, corrosion resistance, or the like. In some cases, the chemical composition of the alloy can exhibit competing effects, for example, it can adversely affect at least one mechanical or chemical property, while at the same time favorably affect at least one other mechanical or chemical property. As described here, one method of balancing the effects of various compositions is to form a modified surface and / or subsurface region, which results in predetermined characteristics of the surface and / or subsurface region, while preserving a different composition, and hence potentially different preset characteristics, in the volume of the alloy.

[0032] In some examples, the methods described herein can only be applied to some parts of an alloy part, such as a turbine engine disk 10. For example, as described above, practically only the rim portion 12 of the disk 10 of the gas turbine engine can be exposed to gases passing through the gas turbine engine. As a consequence, the rim portion 12 may include a modified surface and / or subsurface region, which may contribute to the oxidation and / or corrosion resistance of the rim portion 12, while the drilled hole portion 16 may not include the modified surface and / or subsurface region . In other examples, substantially all surfaces of a gas turbine engine disk 10, including a drilled hole portion 16, a hub portion 14, and a rim portion 12 may include a modified surface and / or subsurface region.

[0033] FIG. 2 is a flowchart of one example of a method for forming a modified surface and / or subsurface region in an alloy substrate, such as a turbine engine disk 10. FIG. 2 will be described while referring to FIGS. 3A and 3B for ease of description. However, it will be understood that the alloy substrate 32 of FIGS. 3A and 3B may form part of the rim portion 12, hub part 14 and / or part 16 with a drilled hole in the disk 10 of the gas turbine engine.

[0034] The method illustrated in FIG. 1 includes forming (22) a layer 36 that includes a plurality of atoms of the surface 34 of the alloy substrate 32. As described above, the alloy substrate 32 may include a nickel alloy, such as a heat resistant nickel-based alloy. In some examples, the alloy substrate 32 may include a nickel alloy that has a phase composition of γ-Ni + γ'-Ni ₃ Al. As will be described below with respect to FIGS. 8 and 9, in some examples, the alloy substrate 32 may be subjected to a heat treatment or other process step that removes substantially all of the tertiary γ'-Ni ₃ Al from at least that portion of the alloy substrate 32 , which will include a modified surface and / or subsurface region. In other examples, the alloy substrate 32 may include any given phase composition and microstructure, including, for example, at least one of primary γ'-Ni ₃ Al, secondary γ'-Ni ₃ Al, and / or tertiary γ'-Ni ₃ Al .

[0035] Layer 36 may include at least one element, and in some examples may consist essentially of a single element. In other examples, layer 36 may include at least two elements. The element or elements in the layer 36 can be selected, for example, from a reactive element or a noble metal. Noble metals used here include Ru, Rh, Pd, Ag, Os, Ir, Pt and Au. Reactive elements used herein include Y, La, Hf, Zr, Ce, Si, and Cr. In some examples, the reactive elements can be divided into subcategories: the main alloying element (Cr), the secondary alloying element (Si) and trace alloying elements (Y, Hf, Zr, La and Ce, collectively called rare-earth reactive elements).

[0036] Layer 36 may be deposited to a thickness (measured in a direction substantially normal to surface 34) or a coating density (measured in g / cm ² ) sufficient to provide a given concentration of the element or elements in the modified surface and / or subsurface region after administration atoms in the layer 36 into the modified surface and / or subsurface region. For example, the thickness or density of the coating, which will lead to a given concentration of the element, can be determined based on the depth of the modified surface and / or subsurface region, measured in a direction almost normal to the surface 34, and a given concentration of the element inside the volume of the modified surface and / or subsurface area.

[0037] Layer 36 can be deposited using any method by which layer 36 can be deposited to an adjustable coating thickness or density. In some examples, a deposition method can be used by which layer 36 can be deposited at relatively low temperatures, for example, below about 1500 ° F (about 815 ° C) or preferably below about 1400 ° F (about 760 ° C). Deposition at a relatively low temperature can facilitate deposition of the layer 36 without significantly affecting the microstructure or phase composition of the substrate 32. Additionally or alternatively, deposition at a relatively low temperature can reduce or substantially eliminate the mutual diffusion of elements between the layer 36 and the alloy substrate 32. In some examples, layer 36 can be vapor deposition (DVD), electrodeposition, nanoscale electrodeposition, chemical vapor deposition of organometallic compounds (MO-CVD), plasma-stimulated physical vapor deposition (PA-PVD), or the like.

[0038] After layer 36 has been deposited on surface 34, layer 36 is subjected to inert ion bombardment using ion bombardment (24). In some examples, inert ions include a noble gas such as He, Ne, Ar, Kr, Xe or Rn. In some embodiments, heavier ions, such as, for example, Xe or Rn, may be preferred.

[0039] Inert ions can be accelerated to layer 36 with an energy level sufficient to collide with atoms in layer 36 and cause atoms to be introduced into alloy substrate 32 to a predetermined depth. For example, inert ions can be accelerated to an energy level sufficient to introduce atoms in the layer 36 into the alloy substrate 32 to a depth of up to about 0.3 μm (measured in a direction almost normal to surface 34). In other examples, inert ions can be accelerated to an energy level sufficient to introduce atoms in the layer 36 into the alloy substrate 32 to a shallower depth, for example, any depth between 0 (zero) μm and about 0.3 μm.

[0040] In some examples, inert ions can be accelerated to various energy levels, so that the atoms in layer 36 are introduced into the alloy substrate 32 at various depths. For example, inert ions can be accelerated to energy levels that cause atoms in the layer 36 to be introduced into the alloy substrate 32 to depths that vary almost continuously from 0 μm to the maximum depth of the modified subsurface region 38. In various examples, the maximum depth of the modified the subsurface region 38 may be from about 0.01 microns to about 0.3 microns. Thus, ion bombardment can be used to introduce atoms of the layer 36 along almost the entire depth of the modified subsurface region 38.

[0041] In some embodiments, the introduction of atoms from the layer 36 into the modified subsurface region 38 can create stress in the alloy substrate 32 at least in the modified subsurface region 38. Stress can impart viscosity to the surface region, similar to other methods for producing compressive surface stresses, such like a freighter. The modified viscosity subsurface region 38 may provide increased resistance to high temperature creep or increased crack propagation resistance in the modified subsurface region 38 compared to an alloy substrate 32 in which such stresses have not been generated.

[0042] In some cases, the use of ion bombardment to form the modified subsurface region 38 in the alloy substrate 32 can contribute to the formation of the modified subsurface region 38 without substantially changing the microstructure and / or phase composition of the alloy substrate 32 in the modified subsurface region 38. For example, as described above, the alloy substrate 32 may include a phase composition of γ-Ni + γ'-Ni ₃ Al before introducing atoms in the layer 36 into the modified subsurface region 38 by an ion bomb radiation. In some examples, the introduction of atoms from layer 36 into the modified subsurface region 38 by ion bombardment leaves the phase composition of γ-Ni + γ'-Ni ₃ Al in the modified subsurface region 38 virtually unchanged.

[0043] In some embodiments, the use of ion bombardment to form the modified subsurface region 38 may contribute to the formation of the modified subsurface region 38, while at the same time leaving the outer dimensions of the alloy substrate 32 unchanged. This may be useful in applications where the dimensions of the alloy substrate 32 are small tolerances and are accurately maintained.

[0044] The ion bombardment step (24) can be carried out at a relatively low temperature, for example, below about 1500 ° F (about 815 ° C) or preferably below about 1400 ° F (about 760 ° C), which, as described above, may not significantly affect the microstructure or phase composition of the alloy substrate 32. Additionally, maintaining the layer 36 and the alloy substrate 32 at a relatively low temperature can reduce or virtually eliminate the mutual diffusion of elements in the alloy substrate 32 and the layer 36.

[0045] After the ion bombardment is completed and the element or elements of layer 36 are introduced into the modified subsurface region 38, the modified subsurface region 38 may include a predetermined number of element or elements that have been deposited in the layer 36. For example, layer 36 may include at least one noble a metal and / or at least one reactive element. In some examples, in which the modified subsurface region 38 includes at least one reactive element, this at least one reactive element may be at least one primary alloying element (Cr), secondary alloying element (Si), or trace alloying element ( Y, Hf, Zr, La, and Ce, collectively, rare-earth reactive elements).

[0046] When the layer 36 includes at least one noble metal, the modified subsurface region 38 may include less than about 20 weight percent (wt.%) Of said at least one noble metal, regardless of whether the layer 36 includes a single noble metal or two or more noble metals. In some examples, the modified subsurface region 38 may include less than about 10 weight percent of said at least one noble metal, regardless of whether layer 36 includes a single noble metal or two or more noble metals. In examples in which the layer 36 includes at least one noble metal, the modified subsurface region 38 may include at least about 1 wt.% Of said at least one noble metal (for example, between about 1 wt.% And about 20 wt. % or between about 1 wt.% and about 10 wt.%). In some examples, the modified subsurface region 38 may include at least about 2.5 weight percent of said at least one noble metal (for example, between about 2.5 weight percent and about 20 weight percent, or between about 2.5 weight % and about 10% by weight).

[0047] When the layer 36 includes Cr, the modified subsurface region 38 may include less than about 30 wt.% Cr. In some examples, the modified subsurface region 38 may include less than about 20 wt.% Cr. In other examples, the modified subsurface region 38 may include less than about 10 wt.% Cr. In examples in which layer 36 includes Cr, the modified subsurface region 38 may include at least about 1 wt.% Cr (for example, between about 1 wt.% And about 30 wt.%, Or between about 1 wt.% And about 20 wt.%, Or between about 1 wt.% And about 10 wt.%). In some examples, the modified subsurface region 38 may include at least about 5 wt.% Cr (for example, between about 5 wt.% And about 30 wt.%, Or between about 5 wt.% And about 20 wt.%, Or between about 5 wt.% and about 10 wt.%).

[0048] When layer 36 includes at least one rare earth reactive element (eg, Y, Hf, Zr, La and / or Ce), the modified subsurface region 38 may include less than about 1 wt.% Of said at least one rare earth reactive an element independent of whether layer 36 includes a single rare earth reactive element or at least two rare earth reactive elements. In some examples, the modified subsurface region 38 may include less than about 0.1% by weight of the at least one rare earth reactive element, whether layer 36 includes a single rare earth reactive element or at least two rare earth reactive elements. In examples in which layer 36 includes at least one rare earth reactive element, the modified subsurface region 38 may include at least about 0.005 wt.% Of said at least one rare earth reactive element (for example, between 0.005 wt.% And about 1 weight % or between 0.005% by weight and about 0.1% by weight). In some examples, the modified subsurface region 38 may include at least about 0.01 weight percent of said at least one rare earth reactive element (for example, between about 0.01 weight percent and about 1 weight percent, or between about 0.01 wt.% and about 0.1 wt.%).

[0049] When the layer 36 includes Si, the modified subsurface region 38 may include less than about 2 wt.% Si. In some examples, the modified subsurface region 38 may include less than about 1 wt.% Si. In examples in which the layer 36 includes Si, the modified subsurface region 38 may include at least about 0.005 wt.% Si (for example, between 0.005 wt.% And about 2 wt.% Or between 0.005 wt.% And about 1 wt. %). In some examples, the modified subsurface region 38 may include at least about 0.01 wt.% Si (for example, between 0.01 wt.% And about 2 wt.% Or between 0.01 wt.% And about 1 wt.% )

[0050] In some examples, layer 36 may include at least one rare earth reactive element and Si. Then, the modified subsurface region 38 may include less than about 2 wt.% In the sum of said at least one rare earth reactive element and Si. In some examples, the modified subsurface region 38 may include less than about 1 wt.% In the sum of the at least one rare earth reactive element and Si.

[0051] In some examples, the composition of the modified subsurface region 38 may vary depending on the depth within the alloy substrate 32. For example, the composition of the modified subsurface region 38 may be more similar to the composition of the alloy substrate 32 at the interface between the modified subsurface region 38 and the alloy substrate 32, and may differ more from the composition of the alloy substrate 32 closer to surface 34. In some examples, such a composition gradient may reduce the risk of peeling or chipping of the modified subsurface region 38 from the alloy substrate 32, for example, may increase the adhesion between the modified subsurface region 38 and the substrate 32 of c melt. In some examples, the above compositions may relate to the average composition within the modified subsurface region 38.

[0052] Although not shown in FIG. 2, in some embodiments, the method may include a heat treatment step after ion bombardment. This heat treatment step can be performed to oxidize Cr or Al present in the modified subsurface region 38 to form an oxide film on surface 34. The oxide film can reduce or virtually eliminate further oxidation and / or corrosion of the alloy substrate 32 and thus can protect the substrate 32 of the alloy from the effects of the environment. Elements present in the modified subsurface region 38 may contribute to the formation of the oxide film, may increase the adhesion of the oxide film to surface 34, or may reduce the rate of further oxidation. For example, Cr can oxidize to form an oxide film. The reactive element can provide oxidation stability, for example, reduce the rate of further oxidation and additionally or alternatively increase the adhesion of the oxide film to surface 34. Noble metals can also contribute to resistance to further oxidation.

[0053] While FIGS. 2, 3A and 3B described a method comprising depositing a single layer 36 on a surface 34, in other embodiments, the method may include depositing multiple layers on a surface 34. In some examples, multiple layers may include various elements. 4, 5A and 5B illustrate one example of such a method.

[0054] As shown in FIG. 4, the method may include depositing (42) the first layer 52 on the surface 34 of the alloy substrate 32. The first layer 52 may include many atoms and includes at least one element. In some examples, the first layer 52 may consist essentially of a single element, while in other examples, the first layer 52 may include at least two elements. As described above, the element or elements may be selected from a reactive element and / or a noble metal.

[0055] The first layer 52 may be deposited to a thickness (measured in a direction substantially normal to surface 34) or a coating density (measured in g / cm ² ) sufficient to provide a given concentration of the element or elements in the modified surface and / or subsurface region after introducing the atoms of the first layer 52 into the modified surface and / or subsurface region. For example, the thickness or density of the coating necessary to provide a given element concentration can be determined based on the depth of the modified surface and / or subsurface region, measured in a direction almost normal to the surface 34, and the given concentration of the element inside the volume of the modified surface and / or subsurface region .

[0056] The first layer 52 can be deposited using any method by which the first layer 52 can be deposited to an adjustable coating thickness or density. In some examples, a deposition method can be used by which the first layer 52 can be deposited at relatively low temperatures, for example, below about 1500 ° F (about 815 ° C) or preferably below about 1400 ° F (about 760 ° C). Precipitation at a relatively low temperature can contribute to the deposition of the first layer 52 without significantly affecting the microstructure or phase composition of the alloy substrate 32. Additionally or alternatively, deposition at a relatively low temperature can reduce or virtually eliminate the mutual diffusion of elements between the first layer 52 and the alloy substrate 32. In some examples, the first layer 52 may be deposited by DVD, electrodeposition, nanoscale electrodeposition, MO-CVD, PA-PVD, or the like.

[0057] After the deposition of the first layer 52 is completed, a second layer 54 may be deposited (44) on the first layer 52. In some examples, the second layer 54 may include at least one element that is not present in the first layer 52. Like the first layer 52, the second layer 54 may include at least one element, and in some examples may consist essentially of a single element. In other examples, the second layer 54 may include at least two elements. The element or elements in the second layer 54 may be selected from a reactive element or a noble metal.

[0058] The second layer 54 may be deposited to a thickness (measured in a direction substantially normal to surface 34) or a coating density (measured in g / cm ² ) sufficient to provide a given concentration of the element or elements in the modified surface and / or subsurface region after introducing atoms of the second layer 54 into the modified surface and / or subsurface region. For example, the thickness or density of the coating necessary to provide a given element concentration can be determined based on the depth of the modified surface and / or subsurface region, measured in a direction almost normal to the surface 34, and the given concentration of the element inside the volume of the modified surface and / or subsurface region .

[0059] The second layer 54 can be deposited using any method by which the second layer 54 can be deposited to an adjustable coating thickness or density. In some examples, a precipitation method can be used by which the second layer 54 can be deposited at relatively low temperatures, for example, below about 1500 ° F (about 815 ° C) or preferably below about 1400 ° F (about 760 ° C). Precipitation at a relatively low temperature can contribute to the deposition of the second layer 54 without significantly affecting the microstructure or phase composition of the alloy substrate 32. Additionally or alternatively, deposition at a relatively low temperature can reduce or virtually eliminate the mutual diffusion of elements between the second layer 54 and the alloy substrate 32. In some examples, the second layer 54 may be deposited by DVD, electrodeposition, nanoscale electrodeposition, MO-CVD, PA-PVD, or the like. In some examples, the first layer 52 and the second layer 54 are deposited using a similar method, while in other examples, the first layer 52 can be deposited using the first method, and the second layer 54 can be deposited using the second method.

[0060] In some examples, a method that involves depositing a first layer 52 and a second layer 54 can independently control the amount of the first element and the second element deposited on surface 34 and introduced into the modified subsurface region 56. For example, the first layer 52 may include the first element, and the second layer 54 may include a second element. In some cases, the deposition of the first element in the first layer 52 and the second element in the second layer 54 may contribute to more accurate control of the deposited amounts of the first and second elements compared to the deposition of the first and second elements as a mixture in a single layer.

[0061] When the first layer 52 and the second layer 54 were deposited on the surface 34, the first and second layers 52 and 54 were subjected to inert ion bombardment using ion bombardment (46). In some examples, inert ions include a noble gas such as He, Ne, Ar, Kr, Xe or Rn. In some embodiments, heavier ions, for example, such as Xe or Rn, may be preferred.

[0062] Inert ions can be accelerated to the first and second layers 52 and 54 with an energy level sufficient to collide with atoms in the first and second layers 52 and 54 and cause atoms to be introduced into the alloy substrate 32 to a predetermined depth. For example, inert ions can be accelerated to an energy level sufficient to introduce atoms of the first and second layers 52 and 54 into the alloy substrate 32 to a depth of up to about 0.3 μm (measured in a direction almost normal to surface 34). In other examples, inert ions can be accelerated to an energy level sufficient to introduce atoms of the first and second layers 52 and 54 into the alloy substrate 32 to a shallower depth, for example, any depth between 0 (zero) μm and about 0.3 μm.

[0063] In some examples, inert ions can be accelerated to various energy levels so that the atoms in the first and second layers 52 and 54 are introduced into the alloy substrate 32 at different depths. For example, inert ions can be accelerated to energy levels that cause atoms in the first and second layers 52 and 54 to be introduced into the alloy substrate 32 to depths that vary almost continuously from 0 μm to the maximum depth of the modified subsurface region 56. B in various examples, the maximum depth of the modified subsurface region 56 may be from about 0.01 μm to about 0.3 μm. Thus, ion bombardment can be used to introduce atoms in the first and second layers 52 and 54 over virtually the entire depth of the modified subsurface region 56.

[0064] The modified subsurface region 56 may have a composition similar or substantially the same as any of the above. For example, the modified subsurface region 56 may include less than about 1 wt.% At least one rare earth reactive element, less than about 2 wt.% Si, less than about 30 wt.% Cr and / or less than about 20 wt.% at least one noble metal. The modified subsurface region 56 may also include other elements, such as those present in the alloy substrate 32, before deposition of the first layer 52 and the second layer 54. As described above, the listed compositions can be average compositions calculated for the entire modified subsurface region 56 in generally, although the composition of the modified subsurface region 56 may vary within the modified subsurface region 56, for example, may vary depending on the depth within the modified no subsurface region 56.

[0065] The ion bombardment step (46) can be carried out at a relatively low temperature, for example, below about 1500 ° F (about 815 ° C) or preferably below about 1400 ° F (about 760 ° C), which, as described above, may not significantly affect the microstructure or phase composition of the alloy substrate 32. Additionally, maintaining the first layer 52, the second layer 54, and the alloy substrate 32 at a relatively low temperature can reduce or virtually eliminate the mutual diffusion of elements in the alloy substrate 32 and layer 36. Optionally, after the ion bombardment step (46), the alloy substrate 32 including modified the subsurface region 56 may be subjected to a heat treatment step. The heat treatment step can be performed to oxidize Cr or Al present in the modified subsurface region to form an oxide film on surface 34. The oxide film reduces or virtually eliminates further oxidation and / or corrosion of the alloy substrate 32 and, thus, can provide protection alloy substrates 32 from exposure to the medium.

[0066] In some examples, as shown in FIGS. 6, 7A, 7B, 7C, and 7D, instead of depositing both the first layer 52 and the second layer 54 on the surface 34, before performing the ion bombardment, the first layer 72 can be deposited (62) on the surface 34 and introduced into the subsurface region of the alloy substrate 32 using ion bombardment (64) to form a modified subsurface region 74. Then, a second layer 76 can be deposited on surface 34 (66), and an element or elements from the second layer 76 can be introduced into modified subsurface region 74 using ion bombardment (68) to form a further modified subsurface region 78 which includes elements of the first layer 72 and second layer 76.

[0067] The first layer 72 may include, for example, at least one element selected from a reactive element and / or a noble metal. Similarly, the second layer 76 may include at least one element selected from a reactive element and / or a noble metal. In some examples, the first layer 72 and the second layer 76 include at least one other element, and in some examples, the first layer 72 may include a single, first element, and the second layer 76 may include a single, different, second element.

[0068] As described above, each of the first layer 72 and the second layer 76 can be deposited to a coating thickness or density that provides a predetermined composition in the modified subsurface region 78 after the introduction of the element (s) in the first layer 72 and the second layer 76. For example , the first layer 72 and the second layer 76 may include sufficient amounts of at least one element so that the modified subsurface region 78 includes less than about 1 wt.% of at least one rare earth reactive element, less than rimerno 2 wt.% Si, less than about 30 wt.% Cr and / or less than about 20 wt.% of at least one noble metal or any other predetermined composition within the ranges listed here.

[0069] In some examples, the methods described herein may include an initial heat treatment step to form a predetermined microstructure in an alloy part (eg, an alloy substrate). For example, as shown in FIGS. 8 and 9, the alloy part may be heated 92 to a heat treatment temperature 94, which is less than the phase transition temperature 100 of the alloy (82). In some examples, as described above, the alloy part may be made of a γ-Ni + γ′-Ni ₃ Al alloy. The phase transition temperature 100 for the γ-Ni + γ'-Ni ₃ Al alloy is called the solvus temperature of γ'-Ni ₃ Al, which is the temperature above which γ'-Ni ₃ Al, including the domains of the primary precipitated phase γ'-Ni ₃ Al, the domains of the secondary precipitated phase γ'-Ni ₃ Al and the domains of the tertiary separated phase γ'-Ni ₃ Al, are almost completely dissolved in the γ-Ni phase with the formation of a solid solution. In some examples, the solvus temperature of γ'-Ni ₃ Al may be between about 1915 ° F (about 1046 ° C) and about 2150 ° F (about 1177 ° C), and the melting point 98 can be between about 2150 ° F (about 1177 ° C) and about 2350 ° F (about 1288 ° C). The solvus temperature of γ'-Ni ₃ Al and the melting temperature 98 will depend on the exact composition of the alloy, and other γ-Ni + γ'-Ni ₃ Al alloys may have a different phase transition temperature 100 and / or a different melting temperature 98.

[0070] In some examples, heat treatment at a temperature below the phase transition temperature of the alloy 100 may result in dissolution of at least some of the domains of the precipitated phases. As one example, a γ-Ni + γ'-Ni ₃ Al alloy may include γ'-Ni ₃ Al domains, which are classified as domains of at least one of the primary, secondary, or tertiary precipitating phase. When a γ-Ni + γ'-Ni ₃ Al alloy is subjected to heat treatment at a temperature of 94 below the temperature of the 100 phase transition temperature of the alloy (82), any domains of the secondary or tertiary precipitating phase of γ'-Ni ₃ Al present in the alloy can practically dissolve in γ-Ni matrix, while any primary domains of the primary precipitating phase of γ'-Ni ₃ Al can remain practically undissolved and can even become larger. For example, a γ-Ni + γ'-Ni ₃ Al alloy part can be heated to a temperature below the solvus temperature of γ'-Ni ₃ Al by between about 75 ° F (about 41.67 ° C) and about 150 ° F ( approximately 83.33 ° C). When the γ-Ni + γ'-Ni ₃ Al alloy is cooled from heat treatment temperature 94 (84), the domains of the secondary precipitated phase of γ'-Ni ₃ Al can form during cooling 96 at relatively high temperatures, while the domains of the tertiary precipitated phase γ '-Ni ₃ Al can form during cooling 96 at lower temperatures. In some examples, if the cooling rate of the alloy part is sufficiently low, domains of the tertiary precipitated phase may not form.

[0071] Once the desired phase composition and microstructure are formed, for example, a microstructure that is substantially free of the domains of the tertiary precipitating phase of γ'-Ni ₃ Al, the method can be continued by the formation of a modified subsurface region. For example, as illustrated in FIG. 8, a layer 36 may be deposited on the surface 34, and an element or elements from the layer 36 may be introduced into the modified subsurface region 38 using ion bombardment (24). In other examples, the method illustrated in FIGS. 8 and 9 may include depositing a first layer and a second layer on surface 34, as illustrated in FIGS. 4 and 5, or FIGS. 6 and 7.

[0072] A variety of examples have been described. These and other examples are within the scope of the following claims.

Claims (20)

1. The method of deposition of the coating on a substrate of heat-resistant nickel alloy, including:
the deposition of a layer of many atoms on the surface of a substrate of heat-resistant Nickel alloy, and many atoms contain at least one of a reactive element or a noble metal,
bombardment of the resulting layer with inert ions to introduce at least some of the many atoms into a substrate of heat-resistant nickel alloy with the formation of a modified subsurface region having a maximum depth of less than about 0.3 μm, measured in a direction almost normal to the surface, and the formation of modified the subsurface region does not affect the microstructure of the substrate of heat-resistant nickel alloy. 2. The method according to claim 1, wherein the inert ions contain at least one of Xe, He, Ne, Ar, Kr, or Rn. 3. The method according to claim 1, wherein the plurality of atoms contains a reactive element, and wherein the reactive element contains at least one of Y, La, Hf, Zr, Ce, Si or Cr. 4. The method according to claim 1, wherein the plurality of atoms contains a noble metal, and wherein the noble metal contains at least one of Ru, Rh, Pd, Pt, Os, Ir, Ag or Au. 5. The method according to claim 1, wherein the plurality of atoms consists essentially of a single element selected from the group consisting of a reactive element or a noble metal. 6. The method according to claim 1, wherein the modified subsurface region of the substrate of heat-resistant nickel alloy contains the phase composition of γ-Ni + γ′-Ni ₃ Al before the bombardment of the layer with inert ions, while the bombardment of the obtained layer with inert ions leaves the γ- phase composition Ni + γ′-Ni ₃ Al in the modified subsurface region of the heat-resistant nickel alloy substrate is practically unchanged. 7. The method according to claim 1, wherein the plurality of atoms contains a reactive element, wherein the reactive element contains at least one rare earth reactive element, and the modified subsurface region contains less than about 1 wt.% Of said at least one rare earth reactive element . 8. The method according to claim 1, wherein the plurality of atoms contains a reactive element, wherein the reactive element contains Si, and the modified subsurface region contains less than about 2 wt.% Si. 9. The method according to claim 1, wherein the plurality of atoms contains a reactive element, wherein the reactive element contains Cr, and wherein the modified subsurface region contains less than about 30 wt.% Cr. 10. The method according to claim 1, wherein the plurality of atoms contains a noble metal, and the modified subsurface region contains less than about 20 wt.% Noble metal. 11. The method according to claim 1, wherein the substrate of heat-resistant nickel alloy contains a phase composition of γ-Ni + γ′-Ni ₃ Al, further comprising:
before the deposition of many atoms in the resulting layer on the surface of a substrate of heat-resistant nickel alloy, heat treatment of the substrate of heat-resistant nickel alloy at a temperature between 41.67 ° C and 83.33 ° C below the solvus temperature of the γ′-Ni ₃ Al alloy to dissolve practically all of the tertiary γ′-Ni ₃ Al present in the subsurface region so that the subsurface region does not substantially contain a tertiary γ′-Ni ₃ Al. 12. The method according to claim 1, further comprising: heat treating the substrate from a heat-resistant nickel alloy including a subsurface region to oxidize Cr or Al present in the subsurface region to form an oxide film on the surface of the subsurface region. 13. An article of heat-resistant nickel alloy, comprising a substrate of heat-resistant nickel alloy, containing:
modified subsurface region; and
volumetric area
moreover, the modified subsurface region contains a first composition, and the volume region contains a second composition different from the first composition, while the modified subsurface region contains at least one of a reactive element or a noble metal, and the modified subsurface region is determined by a maximum thickness of less than about 0 , 3 μm, measured in the direction almost normal to the surface of the substrate of heat-resistant nickel alloy, and the microstructure the modified subsurface region is practically the same as the microstructure of the volume region adjacent to the modified subsurface region. 14. The product according to item 13, while the modified subsurface region contains the phase composition of γ-Ni + γ′-Ni ₃ Al. 15. The product according to item 13, wherein the modified subsurface region contains a reactive element, the reactive element contains at least one of Y, La, Hf, Zr or Ce, and the modified subsurface region contains less than about 1 wt.% said at least one of Y, La, Hf, Zr or Ce. 16. The product according to item 13, while the modified subsurface region contains a reactive element, and the reactive element contains Si, and the modified subsurface region contains less than about 2 wt.% Si. 17. The product according to item 13, while the modified subsurface region contains a reactive element, and the reactive element contains Cr, and the modified subsurface region contains less than about 30 wt.% Cr. 18. The product according to item 13, while the modified subsurface region contains a noble metal, and the modified subsurface region contains less than about 20 wt.% Noble metal. 19. The product according to p. 18, while the noble metal contains at least one of Ru, Rh, Pd, Ag, Os, Ir, Pt and Au. 20. The product according to item 13, further comprising an oxide film formed on the surface of the modified subsurface region, and the oxide film contains at least one of chromium oxide (Cr ₂ O ₃ ) or aluminum oxide (Al ₂ O ₃ ).

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