A two-layer bond alloy for high-temperature alloys and its application

Abstract

This invention discloses a double-layer adhesive alloy for high-temperature alloys and its application, belonging to the field of material surface modification and coating technology. The bottom layer of the double-layer adhesive alloy has the following composition by mass percentage: Al 8.9%-9.4%, Co 7.5%-8.0%, W 4.9%-5.4%, Ta 4.4%-4.9%, Cr 2.6%-3.1%, Ti 1.4%-1.6%, Mo ≤0.2wt%, Hf ≤0.2wt%, with the remainder being Ni. The top layer of the double-layer adhesive alloy has the following composition by mass percentage: Al 19.0%-19.5%, Co 10.0%-10.5%, Cr 6.9%-7.4%, Ta 0.8%-1.0%, Ti 0.2%-0.3%, with the remainder being Ni. This invention targets nickel-based superalloys and designs a double-layer adhesive layer structure. By increasing the Al content in the adhesive layer and combining the concept of phase composition matching and compatibility with the matrix, the coating composition is designed. Under the premise of increasing the Al content in the alloy, the elemental composition of the γ' phase and β phase is determined, and the composition of the double-layer adhesive layer is finally designed.

Description

Technical Field

[0001] This invention belongs to the field of material surface modification and coating technology, specifically relating to a double-layer adhesive alloy for high-temperature alloys and its application. Background Technology

[0002] High-temperature alloys are alloy materials with high-temperature mechanical properties and are widely used in energy, chemical, gas turbine, and aero-engine fields. It is worth noting that high efficiency and high thrust are the perpetual goals of gas turbines and aero-engines. As a special type of heat engine, increasing the gas temperature in gas turbines and aero-engines is a key measure to improve their efficiency and thrust-to-weight ratio. Currently, the gas temperature at the turbine inlet of advanced gas turbines and aero-engines exceeds 2000K, far higher than the operating temperature of high-temperature alloys. To ensure the stable operation of high-temperature alloys in gas environment temperatures exceeding their melting points, film cooling and thermal barrier coating technologies are commonly used to cool and insulate high-temperature alloy components (such as turbine blades). Currently, with the support of advanced film cooling and thermal barrier coating technologies, the gas temperature at the turbine inlet of gas turbines and aero-engines has increased by approximately 300–600℃, significantly improving the efficiency and thrust-to-weight ratio of gas turbines and aero-engines.

[0003] It should be noted that although advanced gas film cooling and thermal barrier coating technologies significantly reduce the thermal effects of high-temperature combustion gases on the surface of high-temperature alloy workpieces, the surface temperature of these workpieces still exceeds 900°C. Such high service temperatures pose a significant challenge to the high-temperature alloy's resistance to hot corrosion and high-temperature oxidation. Because the high-temperature mechanical properties of the alloy were overemphasized in its initial design, the high-temperature alloy itself has relatively weak resistance to high-temperature oxidation and hot corrosion. To enable high-temperature alloy structural components to exhibit excellent resistance to high-temperature oxidation and hot corrosion under high-temperature conditions, a layer of MCrAlY bonding agent is typically prepared on the surface of the high-temperature alloy workpiece to improve its oxidation and hot corrosion resistance.

[0004] It is important to note that current MCrAlY binder layers face two main problems. First, the continuous supply of Al within the binder layer is difficult, leading to the formation of non-alumina oxides and reducing the binder layer's oxidation resistance. Second, due to the significant differences in the alloy element composition and content between the binder layer and the substrate, element interdiffusion is likely to occur, resulting in the deterioration of the mechanical properties of the substrate alloy. Therefore, simultaneously improving the oxidation resistance of the binder layer and reducing interdiffusion between the binder layer and the substrate is a crucial challenge in current binder layer preparation. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a double-layer adhesive alloy for high-temperature alloys and its application, which can improve the high-temperature oxidation resistance of the adhesive layer while reducing the possibility of harmful phases generated by interdiffusion between the adhesive layer and the base alloy.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] This invention discloses a double-layer adhesive alloy for high-temperature alloys. The bottom layer of the double-layer adhesive alloy has the following composition by mass percentage: Al 8.9%-9.4%, Co 7.5%-8.0%, W 4.9%-5.4%, Ta 4.4%-4.9%, Cr 2.6%-3.1%, Ti 1.4%-1.6%, Mo ≤0.2wt%, Hf ≤0.2wt%, and the remainder is Ni.

[0008] The top layer of this double-layer adhesive alloy has the following composition by mass percentage: Al 19.0%-19.5%, Co 10.0%-10.5%, Cr 6.9%-7.4%, Ta 0.8%-1.0%, Ti 0.2%-0.3%, and the remainder Ni.

[0009] Preferably, the bottom layer of the double-layer adhesive alloy has a single-phase γ' phase composition at 800°C; and the top layer of the double-layer adhesive alloy has a single-phase β phase composition at 800°C.

[0010] More preferably, the top β phase is based on the NiAl phase, and the bottom γ' phase is based on the Ni3(Al,Ti) phase.

[0011] Preferably, the bottom and top alloys of the double-layer adhesive layer alloy are prepared by melting raw materials in a melting device according to a set ratio.

[0012] More preferably, the smelting raw materials are pure metals Al, Co, W, Ta, Cr, Ti, Mo, Hf and Ni.

[0013] More preferably, when preparing the double-layer adhesive layer, a single-phase γ' bottom layer is first prepared, and then a single-phase β top layer is prepared on the surface of the single-phase γ' bottom layer.

[0014] The present invention also discloses the application of the above-mentioned high-temperature alloy double-layer adhesive layer alloy as a thermal barrier coating.

[0015] The present invention also discloses the application of the above-mentioned high-temperature alloy double-layer bonding layer alloy in the preparation of hot-end components of gas turbines.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This invention discloses a double-layer adhesive layer alloy for high-temperature alloys. Specifically targeting nickel-based high-temperature alloys, a double-layer adhesive layer structure is designed. By increasing the Al content in the adhesive layer and considering the compatibility of phase composition with the matrix, the coating composition is designed. While increasing the Al content in the alloy, the elemental composition of the γ' and β phases is determined, ultimately resulting in the composition of the double-layer adhesive layer. On one hand, the top β phase is based on the NiAl phase and contains a relatively high amount of Al, providing sufficient Al for forming the Al2O3 film on the adhesive layer surface. On the other hand, the bottom γ' phase is based on the Ni3(Al,Ti) phase, similar in composition to the γ' / γ phases of nickel-based high-temperature alloys, ensuring interfacial compatibility between the bottom adhesive layer and the matrix. Specific advantages include:

[0018] 1) The alloy composition of the designed double-layer adhesive layer is based on nickel-based high-temperature alloys to ensure that the elemental composition of the adhesive layer alloy is as similar as possible to that of the matrix.

[0019] 2) The designed double-layer adhesive layer has a double-layer structure. The top layer consists of a β phase, which provides sufficient Al to form an Al2O3 film on the surface of the top adhesive layer. The bottom layer consists of a γ' phase to ensure interfacial compatibility between the bottom adhesive layer and the substrate. The double-layer adhesive layer can play different roles depending on its location, ensuring that the adhesive layer has resistance to high-temperature oxidation while reducing the formation of harmful phases through interdiffusion with alloying elements in the substrate.

[0020] 3) The designed double-layer adhesive layer is composed of a single phase at the operating temperature and does not contain brittle or harmful phases. Attached Figure Description

[0021] Figure 1 The oxidation kinetics curve of the alloy top adhesive layer prepared in Example 1 of the present invention after oxidation at 800°C for 100 hours;

[0022] Figure 2 The oxidation kinetics curve of the alloy top bonding layer prepared in Example 2 of the present invention after oxidation at 800°C for 100 hours;

[0023] Figure 3 The oxidation kinetics curve of the alloy top layer adhesive layer prepared in Example 3 of the present invention after oxidation at 800°C for 100 hours;

[0024] Figure 4 The oxidation kinetics curve of the alloy top layer adhesive layer prepared in Example 4 of this invention after oxidation at 800℃ for 100h;

[0025] Figure 5 The oxidation kinetics curve of the alloy top adhesive layer prepared in Example 5 of the present invention after oxidation at 800°C for 100 hours. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] This invention discloses a double-layer adhesive layer for high-temperature alloys, wherein the adhesive layer has a double-layer structure. The chemical composition and weight percentage of the bottom layer are as follows: Al 9.4-8.9wt%, Co 8.0-7.5wt%, W 5.4-4.9wt%, Ta 4.9-4.4wt%, Cr 3.1-2.6wt%, Ti 1.6-1.4wt%, Mo ≤0.2wt%, Hf ≤0.2wt%, with the remainder being Ni, and the phase composition at 800℃ is a single-phase γ'. The chemical composition and weight percentage of the top layer are as follows: Al 19.5-10.0wt%, Co 10.5-10wt%, Cr 7.4-6.9wt%, Ta 1.0-0.8wt%, Ti 0.3-0.2wt%, with the remainder being Ni, and the phase composition at 800℃ is a single-phase β.

[0029] The preparation method of the high-temperature alloy double-layer binder alloy of the present invention is as follows: Both the bottom and top layers of the double-layer binder alloy are prepared by melting raw materials in a melting device according to a set ratio. The raw materials are pure metals Al, Co, W, Ta, Cr, Ti, Mo, Hf, and Ni. First, a single-phase γ' bottom layer is prepared, and then a single-phase β top layer is prepared on the surface of the single-phase γ' bottom layer.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings:

[0031] Example 1

[0032] The chemical composition and weight percentage of the double-layer adhesive layer for the high-temperature alloy in this embodiment are as follows: The chemical composition and weight percentage of the bottom layer are as follows: Al 9.4 wt%, Co 8.0 wt%, W 5.4 wt%, Ta 4.9 wt%, Cr 3.1 wt%, Ti 1.6 wt%, Mo 0.2 wt%, Hf 0.2 wt%, and the remainder is Ni. The chemical composition and weight percentage of the top layer are as follows: Al 19.5 wt%, Co 10.5 wt%, Cr 7.4 wt%, Ta 1.0 wt%, Ti 0.3 wt%, and the remainder is Ni.

[0033] The top layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in an atmospheric muffle furnace for high-temperature oxidation experiments. After oxidation at 800°C for 100 hours, the average oxidation rate of the top layer adhesive layer was K. + =0.045g·m -2 ·h -1 The oxide film on the alloy surface consists of a single Al2O3 film, without internal oxidation or composite oxides.

[0034] The bottom layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in a vacuum tube furnace with the base alloy for high-temperature diffusion experiments. After diffusion time of 1050°C and 100 hours, no harmful TCP phase was found at the diffusion interface, indicating that the adhesive layer and the base alloy have good interfacial compatibility.

[0035] Example 2

[0036] The chemical composition and weight percentage of the double-layer adhesive layer for the high-temperature alloy in this embodiment are as follows: The chemical composition and weight percentage of the bottom layer are as follows: Al 9.3 wt%, Co 8.0 wt%, W 5.2 wt%, Ta 4.8 wt%, Cr 3.1 wt%, Ti 1.5 wt%, Mo 0.2 wt%, Hf 0.2 wt%, and the remainder is Ni. The chemical composition and weight percentage of the top layer are as follows: Al 19.3 wt%, Co 10.3 wt%, Cr 7.4 wt%, Ta 1.0 wt%, Ti 0.28 wt%, and the remainder is Ni.

[0037] The top layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in an atmospheric muffle furnace for high-temperature oxidation experiments. After oxidation at 800°C for 100 hours, the average oxidation rate of the top layer adhesive layer was [missing value]. The oxide film on the alloy surface consists of a single Al2O3 film, with no internal oxidation or composite oxides observed.

[0038] The bottom layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in a vacuum tube furnace with the base alloy for high-temperature diffusion experiments. After diffusion time of 1050°C and 100 hours, no harmful TCP phase was found at the diffusion interface, indicating that the adhesive layer and the base alloy have good interfacial compatibility.

[0039] Example 3

[0040] The chemical composition and weight percentage of the double-layer adhesive layer for the high-temperature alloy in this embodiment are as follows: The chemical composition and weight percentage of the bottom layer are as follows: Al 9.1 wt%, Co 7.9 wt%, W 5.4 wt%, Ta 4.7 wt%, Cr 3.0 wt%, Ti 1.6 wt%, Mo 0.18 wt%, Hf 0.2 wt%, and the remainder is Ni. The chemical composition and weight percentage of the top layer are as follows: Al 19.4 wt%, Co 10.4 wt%, Cr 7.5 wt%, Ta 0.8 wt%, Ti 0.25 wt%, and the remainder is Ni.

[0041] The top layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in an atmospheric muffle furnace for high-temperature oxidation experiments. After oxidation at 800°C for 100 hours, the average oxidation rate of the top layer adhesive layer was [missing value]. The oxide film on the alloy surface consists of a single Al2O3 film, with no internal oxidation or composite oxides observed.

[0042] The bottom layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in a vacuum tube furnace with the base alloy for high-temperature diffusion experiments. After diffusion time of 1050°C and 100 hours, no harmful TCP phase was found at the diffusion interface, indicating that the adhesive layer and the base alloy have good interfacial compatibility.

[0043] Example 4

[0044] The chemical composition and weight percentage of the double-layer adhesive layer for the high-temperature alloy in this embodiment are as follows: The chemical composition and weight percentage of the bottom layer are as follows: Al 9.0 wt%, Co 7.8 wt%, W 5.2 wt%, Ta 4.9 wt%, Cr 3.1 wt%, Ti 1.4 wt%, Mo 0.2 wt%, Hf 0.18 wt%, and the remainder is Ni. The chemical composition and weight percentage of the top layer are as follows: Al 19.2 wt%, Co 10.3 wt%, Cr 7.6 wt%, Ta 0.9 wt%, Ti 0.28 wt%, and the remainder is Ni.

[0045] The top layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in an atmospheric muffle furnace for high-temperature oxidation experiments. After oxidation at 800°C for 100 hours, the average oxidation rate of the top layer adhesive layer was [missing value]. The oxide film on the alloy surface consists of a single Al2O3 film, with no internal oxidation or composite oxides observed.

[0046] The bottom layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in a vacuum tube furnace with the base alloy for high-temperature diffusion experiments. After diffusion time of 1050°C and 100 hours, no harmful TCP phase was found at the diffusion interface, indicating that the adhesive layer and the base alloy have good interfacial compatibility.

[0047] Example 5

[0048] The chemical composition and weight percentage of the double-layer adhesive layer for the high-temperature alloy in this embodiment are as follows: The chemical composition and weight percentage of the bottom layer are as follows: Al 8.9 wt%, Co 7.8 wt%, W 5.4 wt%, Ta 4.6 wt%, Cr 3.0 wt%, Ti 1.4 wt%, Mo 0.17 wt%, Hf 0.2 wt%, and the remainder is Ni. The chemical composition and weight percentage of the top layer are as follows: Al 19.0 wt%, Co 10.2 wt%, Cr 7.4 wt%, Ta 1 wt%, Ti 0.29 wt%, and the remainder is Ni.

[0049] The top layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in an atmospheric muffle furnace for high-temperature oxidation experiments. After oxidation at 800°C for 100 hours, the average oxidation rate of the top layer adhesive layer was [missing value]. The oxide film on the alloy surface consists of a single Al2O3 film, with no internal oxidation or composite oxides observed.

[0050] The bottom layer of the double-layer adhesive layer for high-temperature alloys prepared in this embodiment was placed in a vacuum tube furnace with the base alloy for high-temperature diffusion experiments. After diffusion time of 1050°C and 100 hours, no harmful TCP phase was found at the diffusion interface, indicating that the adhesive layer and the base alloy have good interfacial compatibility.

[0051] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A double-layer adhesive alloy for high-temperature alloys, characterized in that, The bottom layer of this double-layer adhesive alloy comprises the following components by mass percentage: Al 8.9%-9.4%, Co 7.5%-8.0%, W 4.9%-5.4%, Ta 4.4%-4.9%, Cr 2.6%-3.1%, Ti 1.4%-1.6%, Mo ≤0.2 wt%, Hf ≤0.2 wt%, with the remainder being Ni; The top layer of this double-layer adhesive alloy has the following composition by mass percentage: Al 19.0%-19.5%, Co 10.0%-10.5%, Cr 6.9%-7.4%, Ta 0.8%-1.0%, Ti 0.2%-0.3%, and the remainder Ni; The bottom layer of the double-layer adhesive alloy has a single-phase γ' phase composition at 800℃; the top layer of the double-layer adhesive alloy has a single-phase β phase composition at 800℃; when preparing the double-layer adhesive layer, a single-phase γ' bottom layer is first prepared, and then a single-phase β top layer is prepared on the surface of the single-phase γ' bottom layer; the top β phase is based on the NiAl phase, and the bottom γ' phase is based on the Ni3(Al, Ti) phase.

2. The double-layer adhesive alloy for high-temperature alloys according to claim 1, characterized in that, The bottom and top alloys of this double-layer bonding layer alloy are both prepared by melting raw materials in a melting device according to a set ratio.

3. The double-layer adhesive alloy for high-temperature alloys according to claim 2, characterized in that, The smelting raw materials are pure metals Al, Co, W, Ta, Cr, Ti, Mo, Hf and Ni.

4. The application of the high-temperature alloy double-layer adhesive layer alloy as described in any one of claims 1 to 3 as a thermal barrier coating.

5. The application of the high-temperature alloy double-layer bonding layer alloy according to any one of claims 1 to 3 in the preparation of hot-end components of gas turbines.

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