CN109554580B

CN109554580B - Nickel-based alloy, preparation method thereof and manufactured article

Info

Publication number: CN109554580B
Application number: CN201810671709.2A
Authority: CN
Inventors: 不公告发明人
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2018-06-26
Filing date: 2018-06-26
Publication date: 2020-10-16
Anticipated expiration: 2038-06-26
Also published as: CN109554580A

Abstract

The invention provides a nickel-based alloy, a preparation method thereof and a manufactured article, wherein the nickel-based alloy consists of the following elements: 5.5 to 6.5 weight percent of aluminum; 5.0 to 7.0 weight percent of chromium; 5.0 wt% -7.0 wt% of cobalt; 5.5 to 7.5 weight percent of molybdenum; 3.0 wt% -5.0 wt% of tungsten; 0.0 wt% to 1.0 wt% titanium; 6.0 wt% -8.0 wt% tantalum; 0.0 wt% to 0.25 wt% hafnium; 0.0 wt% to 0.05 wt% carbon; 0.0 wt% to 0.01 wt% boron; the balance being nickel. By adding the elements and adjusting the content of the elements, the nickel-based alloy realizes good balance in the aspects of alloy density, alloy cost, structure stability, high-temperature strength and the like, and has excellent comprehensive performance.

Description

Nickel-based alloy, preparation method thereof and manufactured article

Technical Field

The invention relates to the technical field of nickel-based alloys, in particular to a nickel-based alloy, a preparation method thereof and a manufactured article.

Background

The high-temperature alloy is a type of alloy developed for high-temperature environment service (above 650 ℃); the alloy usually uses Fe, Co or Ni element as matrix, and also adds a large amount of main alloy elements such as Cr, Al, Ti, Ta, Nb, Mo, W or Re, etc. and trace elements such as C, B, Zr or Hf, etc. The high-temperature alloy is mainly applied to hot-end components of gas turbine engines (including aviation turbine engines and ground gas turbine engines), rocket propellers, nuclear reactors and the like. Compared with iron-based (iron-nickel-based) high-temperature alloy and cobalt-based high-temperature alloy, the nickel-based high-temperature alloy has good oxidation resistance, a face-centered cubic crystal structure with both strength and toughness, higher phase stability and the like, so that the nickel-based high-temperature alloy is widely applied to hot end components of engines.

From the microstructure, the nickel-based superalloy mainly consists of a continuous gamma matrix phase and a discrete gamma' precipitation phase; the gamma phase and the gamma' phase are both in a face-centered cubic structure, the phase interfaces are completely coherent, but the lattice constants have slight difference and lattice mismatching degree. When the composition design of the nickel-based superalloy is not reasonable, the alloy is easy to precipitate topological closely-spaced phases (TCP phases) rich in Cr, Mo, W or Re elements under high-temperature long-service conditions, such as sigma phases, mu phases and P phases. The TCP phase itself is brittle and extracts a large amount of solid solution strengthening elements, thus greatly reducing the high temperature strength of the alloy. The occurrence of TCP phases should be avoided when designing the design.

The development of superalloys is inseparable from the development of gas turbine engines. The gas turbine engine belongs to one of heat engines, and the increase of the temperature of the gas is beneficial to increase of the overall performance of the gas turbine engine, such as increase of combustion efficiency, increase of thrust-weight ratio and reduction of carbon dioxide emission. Therefore, the development of advanced gas turbine engines requires the continuous increase of the service temperature of hot end components such as combustors, high pressure guide vanes, high pressure turbine blades, and the like, and promotes the continuous development of high temperature alloys.

When the turbine blade is in service, the turbine blade is pushed by gas to rotate around the turbine shaft at a high speed, and due to the self weight, the blade generates obvious centrifugal stress, so that the blade material is required to bear the stress for a long time at high temperature, namely, the blade material has good high-temperature creep resistance. Secondly, the existence of residual oxygen in the fuel gas requires that the blade material has good high-temperature oxidation resistance; the long-term high-temperature action requires that the blade material has good structural stability, i.e. does not precipitate brittle TCP phases which reduce the high-temperature strength. In addition, the important physical and mechanical properties of the blade material also include density, hot corrosion resistance, fatigue resistance and the like.

From a microstructural point of view, superalloys produced by deformation or conventional casting are composed of grains of different crystallographic orientation, with grain boundaries between the grains. The grain boundaries are actually a crystal plane defect, with a very severe misarrangement of atoms, with a higher density of vacancies and dislocations than inside the grain. Under the action of high-temperature thermal activation, the grain boundary is easy to be obviously softened, and the bonding strength of the grain boundary is obviously lower than that of the inside of the grain. Therefore, when a load is applied at high temperature, grain boundaries (transverse grain boundaries) perpendicular to the direction of the load more easily become crack origins or crack propagation paths, resulting in a significant decrease in the high-temperature strength of the material.

After the transverse grain boundary is eliminated by the directional solidification process, the high-temperature strength of the nickel-based high-temperature alloy can be obviously improved, so that the directional solidification high-temperature alloy is developed; further, after the crystal boundary is completely eliminated by a single crystal process, the single crystal high-temperature alloy is developed. Because no grain boundary exists, the single crystal high temperature alloy greatly reduces the addition of grain boundary strengthening elements C, B, Zr, Hf and the like. After the content of the elements is limited, the melting point of the alloy is greatly improved, so that the cast structure formed during solidification can be completely eliminated by adopting solution heat treatment at higher temperature, fine and uniform precipitate phase distribution is obtained, and the high-temperature strength of the alloy is improved again.

On the basis of a single crystal process, the addition of the Re element is found to remarkably improve the high-temperature creep resistance of the alloy, which is mainly attributed to that the Re element remarkably reduces the element diffusion at high temperature and inhibits the coarsening of a precipitation phase. The nickel-based single crystal superalloys used today for the manufacture of high pressure turbine blades generally contain the element Re. Nickel-based single crystal superalloys are generally classified into 1 st generation (no Re), 2 nd generation (about 3 wt% Re), 3 rd generation (about 6 wt% Re), and 4 th generation (about 4 wt% Re and 4 wt% Ru) alloys, depending on the amount of Re. However, Re is an extremely rare metal element and is extremely expensive, which leads to a large increase in the manufacturing cost of Re-containing alloys and risks interruption of the Re element supply chain. Therefore, the development of nickel-based single crystal superalloys today must focus on reducing the amount of Re in the alloy, even without adding Re.

However, the existing nickel-based single crystal superalloys AM3, CMSX-2, Ren N4, and the like, although they do not contain Re, have significantly lower high temperature creep strength than the CMSX-4 and Ren N5 alloys that contain 3 wt% Re.

Disclosure of Invention

The technical problem to be solved by the invention is to provide the nickel-based alloy, which can realize good balance in the aspects of alloy density, alloy cost, structural stability, high-temperature strength and the like and has excellent comprehensive performance.

In view of the above, the present application provides a nickel-based alloy consisting of the following elements:

5.5 to 6.5 weight percent of aluminum;

5.0 to 7.0 weight percent of chromium;

5.0 wt% -7.0 wt% of cobalt;

5.5 to 7.5 weight percent of molybdenum;

3.0 wt% -5.0 wt% of tungsten;

0.0 wt% to 1.0 wt% titanium;

6.0 wt% -8.0 wt% tantalum;

0.0 wt% to 0.25 wt% hafnium;

0.0 wt% to 0.05 wt% carbon;

0.0 wt% to 0.01 wt% boron;

the balance being nickel.

Preferably, the content of the aluminum is 5.7 wt% to 6.2 wt%.

Preferably, the content of chromium is 5.2 wt% to 6.8 wt%.

Preferably, the cobalt content is 5.9 wt% to 6.5 wt%.

Preferably, the content of the molybdenum is 6.0 wt% to 7.0 wt%.

Preferably, the content of tungsten is 3.2 wt% to 4.8 wt%.

Preferably, the content of titanium is 0.1 wt% to 0.8 wt%.

Preferably, the content of the tantalum is 6.5 wt% to 7.1 wt%.

Preferably, it consists of the following elements: 5.95 wt% aluminum, 5.8 wt% chromium, 6.2 wt% cobalt, 6.5 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

Preferably, it consists of the following elements: 5.95 wt% aluminum, 5.8 wt% chromium, 6 wt% cobalt, 6.4 wt% molybdenum, 3.8 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

Preferably, it consists of the following elements: 6.03 wt% aluminum, 6.0 wt% chromium, 6.2 wt% cobalt, 6.5 wt% molybdenum, 3.72 wt% tungsten, 0.22 wt% titanium, 6.8 wt% tantalum, 0.09 wt% hafnium, 0.03 wt% carbon, 0.003 wt% boron, and the balance nickel.

The application also provides a preparation method of the nickel-based alloy, which comprises the following steps:

A) preparing a nickel-based master alloy ingot according to the component ratio;

B) remelting the nickel-based master alloy ingot, and preparing a nickel-based alloy casting;

C) and carrying out heat treatment on the nickel-based alloy casting to obtain the nickel-based alloy.

Preferably, the nickel-based alloy casting includes an isometric crystal casting prepared using an investment casting method, a columnar crystal casting prepared based on Bridgman's orientation solidification, or a single crystal casting prepared based on Bridgman's orientation solidification.

Preferably, the heat treatment specifically comprises:

carrying out solution treatment on the nickel-based alloy casting for 2-12 h at 1280-1340 ℃, and then carrying out air cooling; carrying out high-temperature aging treatment at 1050-1150 ℃ for 2-8 h, and then carrying out air cooling; and then carrying out low-temperature aging treatment at 850-950 ℃ for 12-20 h, and then carrying out air cooling to finally obtain the nickel-based alloy with uniform structure.

The application also provides an article of manufacture applied to a gas turbine engine, which is prepared from the nickel-based alloy in the scheme.

Preferably, the article of manufacture is a gas turbine engine turbine blade.

The application provides a nickel-based alloy, which consists of the following elements: 5.5 to 6.5 weight percent of aluminum; 5.0 to 7.0 weight percent of chromium; 5.0 wt% -7.0 wt% of cobalt; 5.5 to 7.5 weight percent of molybdenum; 3.0 wt% -5.0 wt% of tungsten; 0.0 wt% to 1.0 wt% titanium; 6.0 wt% -8.0 wt% tantalum; 0.0 wt% to 0.25 wt% hafnium; 0.0 wt% to 0.05 wt% carbon; 0.0 wt% to 0.01 wt% boron; the balance being nickel. In the nickel-based alloy of the present application, the Al content can promote about 55-70% of gamma' -Ni in volume fraction to be precipitated in the alloy₃Al precipitation phase, and simultaneously ensuring that Al is generated on the surface of the alloy at high temperature₂O₃Continuity of the film; cr with proper content can avoid the precipitation of a TCP phase, is beneficial to the addition of solid solution strengthening elements and is beneficial to improving the high-temperature strength of the alloy; co can form a continuous replacement solid solution in nickel, the stacking fault energy of a gamma matrix phase is reduced, and the solidus temperature and the gamma' phase dissolution temperature of the alloy are improved to a certain extent; therefore, the nickel-based alloy provided by the application realizes good balance in the aspects of alloy density, alloy cost, structure stability, high-temperature strength and the like on the basis of no Re and proper amount of tungsten by increasing the total content of Mo, W and Ta, adding a plurality of alloy elements and controlling the content of the alloy elements, and has excellent comprehensive performance.

Drawings

FIG. 1 is a flow chart illustrating the preparation of a nickel-based alloy according to the present invention;

FIG. 2 is a bar graph comparing the cost of nickel-based alloys provided by embodiments of the present invention to prior art alloys;

FIG. 3 is a bar graph comparing the density of nickel-based alloys provided in accordance with embodiments of the present invention and prior art alloys;

FIG. 4 is a bar graph comparing the average electron vacancy number, Nv, for nickel-based alloys provided in accordance with embodiments of the present invention and prior art alloys;

FIG. 5 is a bar graph comparing the average d orbital level Md of nickel-based alloys provided in accordance with embodiments of the present invention with the prior art alloys;

FIG. 6 is a bar graph comparing thermodynamic and structural parameters of a nickel-based alloy in accordance with an embodiment of the present invention with those of a prior art alloy;

fig. 7 is a microscopic metallographic photograph of a nickel-based alloy prepared in example 7 of the present invention.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

Aiming at the problems that the nickel-based alloy in the prior art does not contain Re but has low high-temperature creep strength, the invention provides the nickel-based alloy, which develops the nickel-based single crystal superalloy which does not contain Re but has high-temperature strength, particularly high-temperature creep strength close to that of the nickel-based single crystal superalloy containing Re through the strengthening action of balanced alloy elements, and simultaneously considers other important properties, such as good phase stability, oxidation resistance and the like. Specifically, the nickel-based superalloy disclosed by the application consists of the following elements:

5.5 to 6.5 weight percent of aluminum;

5.0 to 7.0 weight percent of chromium;

5.0 wt% -7.0 wt% of cobalt;

5.5 to 7.5 weight percent of molybdenum;

3.0 wt% -5.0 wt% of tungsten;

0.0 wt% to 1.0 wt% titanium;

6.0 wt% -8.0 wt% tantalum;

0.0 wt% to 0.25 wt% hafnium;

0.0 wt% to 0.05 wt% carbon;

0.0 wt% to 0.01 wt% boron;

the balance being nickel.

In the nickel-based alloy of the present application, aluminum (Al) is a main element forming a γ' phase, and brings a significant precipitation strengthening effect to the alloy. In addition, Al element is easy to generate compact Al on the surface of alloy at high temperature₂O₃The film can prevent the diffusion of oxygen element into the alloy, thereby improving the oxidation resistance of the alloy. The aluminum content is 5.5 wt% -6.5 wt%, and the aluminum in the content range can promote the precipitation of gamma' -Ni with the volume fraction of about 55-70% in the alloy₃Al precipitation phase, and simultaneously ensuring that Al is generated on the surface of the alloy at high temperature₂O₃Continuity of the film. In certain embodiments, the aluminum is present in an amount of 5.6 wt% to 6.3 wt%; in certain embodiments, the aluminum is present in an amount of 5.7 wt% to 6.2 wt%.

Chromium (Cr) is mainly segregated in a gamma matrix phase and plays a small role in solid solution strengthening; cr has high oxidation resistance and hot corrosion resistance, and the existence of Cr can promote Al at high temperature₂O₃The film is formed, so that the oxidation resistance of the alloy is improved; however, too high Cr content causes easy precipitation of TCP phase in the alloy, and limits the addition of the strengthening elements Re, W, Mo and the like, which is not favorable for the high-temperature strength of the alloy. Through adjustment, the content of chromium is 5.0 wt% -7.0 wt%; in certain embodiments, the chromium content is 5.2 wt% to 6.8 wt%; in certain embodiments, the chromium is present in an amount of 5.8 wt% to 6.2 wt%.

Cobalt (Co) can form a continuous replacement solid solution in nickel, reduce the stacking fault energy of a gamma matrix phase and improve the solidus temperature and the dissolution temperature of a gamma' phase of the alloy to a certain extent; however, Co is less resource-intensive and expensive relative to Ni, and excessive Co also tends to cause formation of TCP phases. Through adjustment, the content of the cobalt is 5.0 wt% -7.0 wt%; in certain embodiments, the cobalt content is 5.9 wt% to 6.5 wt%; in certain embodiments, the cobalt is present in an amount of 6.0 wt% to 6.2 wt%.

Molybdenum (Mo) is mainly segregated in a gamma matrix phase, plays a remarkable role in solid solution strengthening and improves the high-temperature strength of the alloy. In addition, the lower density of Mo relative to W can relieve the adverse effect of refractory element addition on the alloy density. However, Mo itself is poor in oxidation resistance and hot corrosion resistance, and excessive Mo content is liable to promote precipitation of TCP phase. The content of the molybdenum is 5.5 wt% -7.5 wt% after adjustment; in certain embodiments, the molybdenum is present in an amount of 6 wt% to 7 wt%; in certain embodiments, the molybdenum is present in an amount of 6.3 wt% to 6.7 wt%.

The strengthening behavior of tungsten (W) is very similar to that of Mo and is mainly segregated in a gamma matrix phase, but W has a lower diffusion rate relative to Mo, so that the coarsening rate of a gamma' phase can be effectively reduced, and the creep life can be prolonged. In the absence of Re, W is the most important solid-solution strengthening element and can partially replace the strengthening effect of Re, but too high W also causes the alloy to be easy to precipitate a TCP phase. Through adjustment, the content of tungsten is 3.0 wt% -5.0 wt%; in certain embodiments, the tungsten is present in an amount of 3.2 wt% to 4.8 wt%; in certain embodiments, the tungsten is present in an amount of 3.6 wt% to 3.9 wt%.

Titanium (Ti) is mainly segregated in the gamma 'phase and can replace the position of Al to form more gamma' phases to play a role in strengthening precipitation. Ti can more effectively raise the solution temperature of the gamma ' phase and the lattice constant of the gamma ' phase relative to Al, and provides additional strengthening effect by increasing the antiphase domain boundary energy of the gamma ' phase. However, excessive Ti is detrimental to the castability of the alloy and causes an increased degree of segregation of Cr and Mo in the gamma phase, thereby increasing the risk of the alloy precipitating TCP phases. The content of the titanium is adjusted to be 0.0 wt% -1.0 wt%; in certain embodiments, the titanium is present in an amount of 0.1 wt% to 0.8 wt%; in certain embodiments, the titanium is present in an amount of 0.15 wt% to 0.35 wt%.

The effect of tantalum (Ta) in the single-crystal high-temperature alloy is similar to that of Ti, the tantalum (Ta) is mainly segregated in a gamma ' phase, the volume fraction of the gamma ' phase is increased, but the tantalum (Ta) has higher high-temperature strengthening effect compared with Ti element, and the solid solution temperature, solidus temperature, tensile strength and creep resistance of the gamma ' phase of the alloy can be obviously improved. However, Ta itself is a relatively expensive metal and has a high density relative to other alloying elements, and too high Ta causes a large increase in alloy density and cost. The content of the tantalum is 6.0 wt% -8.0 wt% after adjustment; in certain embodiments, the tantalum is present in an amount of 6.5 wt% to 7.1 wt%; in certain embodiments, the tantalum is present in an amount of 6.8 wt% to 7.0 wt%.

Hafnium (Hf) is present in single crystal superalloys in the form of trace elements. The trace amount of Hf can effectively adsorb harmful impurity element S in the alloy, so that the strength and the toughness of the alloy are increased, and meanwhile, the adhesion of a coating can be increased, so that the environmental resistance of the alloy is improved. However, Hf significantly lowers the melting point of the alloy, lowering the heat treatment window of the alloy. The content of the hafnium is adjusted to be 0.0 wt% -0.25 wt%; in certain embodiments, the hafnium is present in an amount of 0.05 wt% to 0.20 wt%; in certain embodiments, the hafnium is present in an amount of 0.08 wt% to 0.12 wt%.

The elements of carbon (C) and boron (B) are also present in the form of trace elements in the single crystal superalloy. They tend to segregate at the subgrain boundary of the alloy and form carbide or boride with alloying elements such as Ti, Ta, Mo, W and the like to strengthen the subgrain boundary, thereby reducing the subgrain boundary cracking tendency of the alloy; but C and B can significantly lower the melting point of the alloy. The content of carbon is adjusted to be 0.0 wt% -0.05 wt%; the boron content is 0.0 wt% -0.01 wt%. In certain embodiments, the carbon is present in an amount of 0.02 wt% to 0.04 wt%; the content of boron is 0.002 wt% -0.004 wt%.

In certain embodiments, the nickel-based alloy consists of the following elements: 6.05 wt% aluminum, 5.8 wt% chromium, 6.2 wt% cobalt, 6.4 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 6.8 wt% tantalum and the balance nickel.

In certain embodiments, the nickel-based alloy consists of the following elements: 5.95 wt% aluminum, 5.8 wt% chromium, 6.2 wt% cobalt, 6.5 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

In certain embodiments, the nickel-based alloy consists of the following elements: 6.05 wt% aluminum, 5.8 wt% chromium, 6 wt% cobalt, 6.4 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 6.8 wt% tantalum and the balance nickel.

In certain embodiments, the nickel-based alloy consists of the following elements: 5.95 wt% aluminum, 5.8 wt% chromium, 6 wt% cobalt, 6.4 wt% molybdenum, 3.8 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

In certain embodiments, the nickel-based alloy consists of the following elements: 6.05 wt% aluminum, 5.8 wt% chromium, 6 wt% cobalt, 6.5 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 6.6 wt% tantalum and the balance nickel.

In certain embodiments, the nickel-based alloy consists of the following elements: 5.95 wt% aluminum, 5.8 wt% chromium, 6.2 wt% cobalt, 6.4 wt% molybdenum, 3.8 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

In certain embodiments, the nickel-based alloy consists of the following elements: 6.03 wt% aluminum, 6.0 wt% chromium, 6.2 wt% cobalt, 6.5 wt% molybdenum, 3.72 wt% tungsten, 0.22 wt% titanium, 6.8 wt% tantalum, 0.09 wt% hafnium, 0.03 wt% carbon, 0.003 wt% boron, and the balance nickel.

A) preparing a nickel-based master alloy ingot according to the component proportion of the nickel-based alloy;

In the above method for preparing the nickel-based alloy, the specific composition of the nickel-based master alloy ingot is described in detail above, and is not described herein again.

In the above process for preparing the nickel-based alloy, the method for preparing the nickel-based master alloy ingot is performed according to a method well known to those skilled in the art, and by way of example, the raw materials are put into a vacuum smelting furnace according to the component proportion to be smelted so as to obtain the nickel-based master alloy ingot.

According to the invention, the nickel-based master alloy ingot is then remelted in a manner well known in the art, for example, in a vacuum apparatus; and preparing a nickel-based alloy casting, wherein the nickel-based alloy casting can be prepared into a columnar crystal casting by a directional solidification method according to needs, and can also be prepared into a single crystal casting by a spiral crystal selection method or a seed crystal method.

The nickel-based alloy casting is finally subjected to heat treatment according to a well-known manner of the nickel-based alloy; in the application, the heat treatment is performed in sequence according to the steps of solid solution treatment, cooling, high-temperature aging treatment, cooling, low-temperature aging treatment and cooling, specifically, the temperature of the solid solution treatment is 1280-1340 ℃, the time is 2-12 hours, the temperature of the high-temperature aging treatment is 1050-1150 ℃, the time is 2-8 hours, the temperature of the low-temperature aging treatment is 850-950 ℃, the time is 12-20 hours, and the cooling mode is air cooling or forced gas quenching.

In a specific embodiment, the nickel-based alloy is prepared and molded through a vacuum induction melting and directional solidification process, and the preparation flow chart of the method is shown in fig. 1, specifically, (1) the alloy material with the components is prepared through vacuum induction melting, and a master alloy ingot with accurately controlled components is obtained; (2) remelting the ingot casting material, and preparing a single crystal casting or a directional casting by a directional solidification process; (3) obtaining a casting with proper size through machining; (4) the cast structure in the alloy is eliminated through heat treatment, and the optimal microstructure is obtained.

In accordance with an embodiment of the present invention, the nickel-based alloy described herein is formed in a manner to fabricate an article that is applicable to a gas turbine engine, and more particularly, to a gas turbine engine turbine blade, prepared from an alloy comprising: 5.5 to 6.5 weight percent of aluminum; 5.0 to 7.0 weight percent of chromium; 5.0 wt% -7.0 wt% of cobalt; 5.5 to 7.5 weight percent of molybdenum; 3.0 wt% -5.0 wt% of tungsten; 0.0 wt% to 1.0 wt% titanium; 6.0 wt% -8.0 wt% tantalum; 0.0 wt% to 0.25 wt% hafnium; 0.0 wt% to 0.05 wt% carbon; 0.0 wt% to 0.01 wt% boron; the balance being nickel.

In certain embodiments, the article of manufacture is prepared from an alloy comprising: 6.05 wt% aluminum, 5.8 wt% chromium, 6.2 wt% cobalt, 6.4 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 6.8 wt% tantalum and the balance nickel.

In certain embodiments, the article of manufacture is prepared from an alloy comprising: 5.95 wt% aluminum, 5.8 wt% chromium, 6.2 wt% cobalt, 6.5 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

In certain embodiments, the article of manufacture is prepared from an alloy comprising: 6.05 wt% aluminum, 5.8 wt% chromium, 6 wt% cobalt, 6.4 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 6.8 wt% tantalum and the balance nickel.

In certain embodiments, the article of manufacture is prepared from an alloy comprising: 5.95 wt% aluminum, 5.8 wt% chromium, 6 wt% cobalt, 6.4 wt% molybdenum, 3.8 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

In certain embodiments, the article of manufacture is prepared from an alloy comprising: 6.05 wt% aluminum, 5.8 wt% chromium, 6 wt% cobalt, 6.5 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 6.6 wt% tantalum and the balance nickel.

In certain embodiments, the article of manufacture is prepared from an alloy comprising: 5.95 wt% aluminum, 5.8 wt% chromium, 6.2 wt% cobalt, 6.4 wt% molybdenum, 3.8 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

In certain embodiments, the article of manufacture is prepared from an alloy comprising: 6.03 wt% aluminum, 6.0 wt% chromium, 6.2 wt% cobalt, 6.5 wt% molybdenum, 3.72 wt% tungsten, 0.22 wt% titanium, 6.8 wt% tantalum, 0.09 wt% hafnium, 0.03 wt% carbon, 0.003 wt% boron, and the balance nickel.

For further understanding of the present invention, the nickel-based alloy provided by the present invention will be described in detail with reference to the following examples, and the scope of the present invention is not limited by the following examples.

Examples

The nickel-based high-temperature alloy realizes good balance in the aspects of alloy density, alloy cost, structure stability, high-temperature strength and the like, and has excellent comprehensive performance. To further illustrate the effectiveness of the present application, 7 specific examples are listed, 6 of which are compared to 5 prior alloys. The composition of the 7 example alloys and the 5 prior alloys are shown in table 1; in an embodiment, the preparation method of the nickel-based superalloy specifically comprises the following steps:

1) putting the raw materials with the component proportions shown in the table 1 into a vacuum induction smelting furnace to smelt an alloy, and preparing a master alloy ingot;

2) remelting the mother alloy ingot in vacuum equipment, and preparing a columnar crystal casting by a directional solidification method or preparing a single crystal casting by a spiral crystal selection method or a seed crystal method in a mould shell formed by refractory materials;

3) carrying out solution treatment on the casting for 2-12 h at 1280-1340 ℃, and then carrying out air cooling; carrying out high-temperature aging treatment at 1050-1150 ℃ for 2-8 h, and then carrying out air cooling; and then carrying out low-temperature aging treatment at 850-950 ℃ for 12-20 h, and then carrying out air cooling to finally obtain the nickel-based high-temperature alloy with uniform structure.

TABLE 1 composition data (wt%) of the nickel-base superalloys provided in the examples and prior art

1) The alloy cost is greatly reduced compared with the Re-containing alloy

And calculating the raw material cost of each alloy according to the raw material component ratio of the alloy and the market price of each raw material in 12 months in 2017. The cost of 6 examples of the alloy of the present application versus 5 prior alloys is shown in fig. 2. As can be seen from FIG. 2, the cost of the 6 examples is reduced by about 76% relative to an alloy containing about 3 wt% of CMSX-4 and Ren N5; the cost of 6 examples was slightly higher, but at the same level, than the Re-free AM3, CMSX-2, and Ren N4 alloys. Thus, the cost of the alloy is well controlled.

2) The density of the alloy is controlled in a reasonable range

Alloy density is one of the main factors that determine the magnitude of centrifugal stress experienced by the rotating member during operation and is therefore a design consideration. FIG. 3 is a bar graph comparing the calculated densities of 6 examples of the alloy of the present application and 5 prior alloys. Due to the strengthening effect of replacing Re by a large amount of refractory elements W + Mo + Ta, the density of the alloy of the invention is equivalent to that of the alloy CMSX-2 without Re, is slightly higher than that of the alloys AM3 and Ren N4, but is slightly lower than that of the alloy CMSX-4 with Re and Ren N5, thereby showing that the density of the nickel-based alloy of the invention is still controlled within a reasonable range.

3) Has good tissue stability

The alloy has good structural stability under long-term high-temperature aging, and is not easy to precipitate harmful TCP phase. FIG. 4 is a bar graph comparing the average electron vacancy number Nv for 6 examples of the alloy of the present application with 5 prior alloys according to the PHACOMP method; FIG. 5 is a bar graph comparing the average d orbital level Md of 6 examples of the alloy of the present application with 5 prior alloys according to the New PHOCOMP method; as can be seen from FIG. 4, the Nv values of the alloys of the present application are all significantly lower than the calculated values for the prior alloys CMSX-2, AM3, Ren N4, CMSX-4 and Ren N5; as can be seen from FIG. 5, the Md value of the alloy of the present application is comparable to that of the alloy AM3, significantly lower than that of the alloy Ren N4 and slightly higher than the calculated values of the alloys CMSX-2, Ren N5 and CMSX-4. Comprehensively, the nickel-based alloy has good structural stability.

4) Has excellent high temperature creep resistance

The present application considers the high temperature creep resistance of the alloy from 4 aspects: (1) the phase transition temperature of the alloy; (2) the degree of solid solution strengthening of the alloy; (3) the amount of precipitation strengthening phases of the alloy; (4) lattice mismatch of the alloy.

The 3 important phase transition temperatures of nickel-base superalloys are: the solid solution temperature of the gamma 'phase, namely the critical temperature at which the gamma' phase is completely dissolved into the gamma phase along with the temperature rise; solidus temperature, namely the critical temperature at which the alloy begins to melt as the temperature rises; and the liquidus temperature, namely the critical temperature of the alloy which is completely melted along with the temperature rise. The higher the solid solution temperature of the gamma 'phase is, the more gamma' phases which are not dissolved at high temperature are, and the higher the high-temperature precipitation strengthening effect of the alloy is; the higher the solidus and liquidus temperatures are, the higher the temperature resistance of the alloy itself is. FIG. 6(a) is a bar graph comparing calculated values of the gamma prime solution temperature, solidus temperature and liquidus temperature for 6 examples of the alloy of the present application with 5 prior art alloys, and it can be seen from FIG. 6(a) that the gamma prime solution temperature for 6 examples of the alloy of the present application is comparable to that of the alloys CMSX-2, AM3, CMSX-4, higher than the alloy Ren N4 and slightly lower than the alloy Ren N5; the solidus and liquidus temperatures are comparable to the alloys CMSX-2, AM3, CMSX-4 and Ren N5, slightly above the alloy Ren N4.

The solid solution strengthening degree of the alloy mainly considers the effects of 3 strong solid solution strengthening elements Re, W and Mo. The application adopts a solid solution strengthening factor I_SSSThe degree of solid solution strengthening of the alloy was evaluated. I is_SSSThe higher the degree of solid solution strengthening of the alloy. FIG. 6(b) shows 6 examples of the alloy of the present application and 5 conventional alloys I_SSSComparative bar chart of calculated values, as can be seen from FIG. 6(b), I of 6 examples due to the addition of large amounts of W and Mo_SSSSignificantly higher than those calculated for the alloys CMSX-2, Ren N4 and AM3, at the same level as those calculated for the alloys CMSX-4, Ren N5.

The precipitation strengthening degree of the alloy mainly considers the fraction of a gamma' phase in the alloy at the service temperature, and the higher the value of the precipitation strengthening degree is, the greater the potential of the precipitation strengthening of the alloy is. FIG. 6(c) is a bar graph comparing the mole fraction of gamma prime phases at 850 deg.C, 900 deg.C, 1050 deg.C and 1100 deg.C for 6 examples of the alloy of the present application and 5 prior alloys, respectively, as calculated by Thermo-Calc; as can be seen from FIG. 6(c), the molar fractions of the gamma prime phases of the 6 examples are not lower than the corresponding values for the alloys Ren N4, CMSX-4 and Ren N5, at the same temperature, which are comparable to the alloys CMSX-2 and AM 3.

Another key parameter related to creep strength of alloys is the lattice mismatch of the gamma/gamma' phase. Research shows that the lattice mismatching degree is negative, and the higher the absolute value is, the creep strength is increased, but the higher the mismatching degree is, the two-phase coherent structure of gamma/gamma' is unstable, and the coherent strengthening effect is lost. It is generally accepted that the lattice mismatch should not be higher than 0.5%. FIG. 6(d) is a bar graph comparing calculated lattice misfits for 6 examples of the alloy of the present application with those of 5 prior art alloys, and it can be seen from FIG. 6(d) that the lattice misfits for the alloy of the present application are negative, all above the calculated values for the alloys CMSX-2, AM3, Ren N4, CMSX-4 and Ren N5, but below 0.5%.

5) Observation of microstructure and durability of example 7

As shown in fig. 7, fig. 7 is a microstructure photograph of the nickel-based alloy prepared in example 7, and table 2 is a durability data table of the nickel-based alloy prepared in example 7;

TABLE 2 table of durability data for nickel-base alloys prepared in example 7

Test conditions	Long life, h	Elongation percentage of%	Reduction of area fraction%
				850℃/650MPa	24.3	23	34
982℃/248MPa	27.6	31	48
				1040℃/145MPa	67.6	14	49

The manufactured article formed by the nickel-based alloy prepared in the embodiment is particularly applied to a turbine blade of a gas turbine engine, and has the same performance as the nickel-based alloy.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A nickel-base alloy consisting of the following elements:

5.5 to 6.5 weight percent of aluminum;

5.0 to 7.0 weight percent of chromium;

5.0 wt% -7.0 wt% of cobalt;

5.5 to 7.5 weight percent of molybdenum;

3.0 wt% -5.0 wt% of tungsten;

0.0 wt% to 1.0 wt% titanium;

6.0 wt% -8.0 wt% tantalum;

0.0 wt% to 0.25 wt% hafnium;

0.0 wt% to 0.05 wt% carbon;

0.0 wt% to 0.01 wt% boron;

the balance being nickel.

2. The nickel-base alloy of claim 1, wherein the aluminum is present in an amount of 5.7 wt% to 6.2 wt%.

3. The nickel-base alloy of claim 1, wherein the chromium is present in an amount of 5.2 wt% to 6.8 wt%.

4. The nickel-base alloy of claim 1, wherein the cobalt content is between 5.9 wt% and 6.5 wt%.

5. The nickel-base alloy of claim 1, wherein the molybdenum is present in an amount of 6.0 wt% to 7.0 wt%.

6. The nickel-base alloy of claim 1, wherein the tungsten is present in an amount of 3.2 wt% to 4.8 wt%.

7. The nickel-base alloy of claim 1, wherein the titanium is present in an amount of 0.1 wt% to 0.8 wt%.

8. The nickel-base alloy of claim 1, wherein the tantalum is present in an amount of 6.5 wt% to 7.1 wt%.

9. The nickel-base alloy according to claim 1, consisting of the following elements: 5.95 wt% aluminum, 5.8 wt% chromium, 6.2 wt% cobalt, 6.5 wt% molybdenum, 3.7 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

10. The nickel-base alloy according to claim 1, consisting of the following elements: 5.95 wt% aluminum, 5.8 wt% chromium, 6 wt% cobalt, 6.4 wt% molybdenum, 3.8 wt% tungsten, 0.15 wt% titanium, 7 wt% tantalum and the balance nickel.

11. The nickel-base alloy according to claim 1, consisting of the following elements: 6.03 wt% aluminum, 6.0 wt% chromium, 6.2 wt% cobalt, 6.5 wt% molybdenum, 3.72 wt% tungsten, 0.22 wt% titanium, 6.8 wt% tantalum, 0.09 wt% hafnium, 0.03 wt% carbon, 0.003 wt% boron, and the balance nickel.

12. The method for producing the nickel-base alloy according to any one of claims 1 to 11, comprising the steps of:

13. The production method according to claim 12, wherein the nickel-based alloy casting includes an equiaxed grain casting produced using an investment casting method, a columnar grain casting produced based on bridgman's orientation solidification, or a single crystal casting produced based on bridgman's orientation solidification.

14. The method according to claim 12, wherein the heat treatment is in particular:

15. An article of manufacture for use in a gas turbine engine, made from the nickel-base alloy of any of claims 1 to 11.

16. The article of manufacture of claim 15, wherein the article of manufacture is a gas turbine engine turbine blade.