CN109554580B - A kind of nickel-based alloy, its preparation method and manufactured article - Google Patents

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

A kind of nickel-based alloy, its preparation method and manufactured article

technical field

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

Background technique

Superalloys are a class of alloys developed for service in high temperature environments (above 650°C); such alloys usually use Fe, Co or Ni as the matrix, and also add a large number of main alloying elements Cr, Al, Ti, Ta, Nb, Mo, W or Re, etc. and trace elements C, B, Zr or Hf, etc. Superalloys are mainly used in hot-end components of gas turbine engines (including aviation turbine engines and ground gas turbine engines), rocket propulsion and nuclear reactors. Compared with iron-based (iron-nickel-based) superalloy and cobalt-based superalloy, nickel-based superalloy itself has better oxidation resistance, and has a face-centered cubic crystal structure that combines strength and toughness, and higher phase stability etc., so it is more widely used in engine hot end parts.

From the microstructure point of view, nickel-based superalloys are mainly composed of continuous γ matrix phase and discrete γ′ precipitated phases; both γ and γ′ phases are face-centered cubic structures, and the phase interface is completely coherent, but the lattice constant exists A small difference exists in the degree of lattice mismatch. When the composition design of nickel-based superalloys is unreasonable, topologically densely packed phases (TCP phases) rich in Cr, Mo, W or Re elements, such as σ phase, μ phase and P phase, are prone to precipitate out of the alloy under high temperature and long-term service conditions. equal. The TCP phase itself is brittle and extracts a large amount of solid solution strengthening elements, so it will greatly reduce the high temperature strength of the alloy. The appearance of the TCP phase should be avoided in the design.

The development of superalloys is inseparable from the development of gas turbine engines. A gas turbine engine is a type of heat engine. Increasing the temperature of the gas is beneficial to increase the overall performance of the gas turbine engine, such as increasing the combustion efficiency, thereby increasing the thrust-to-weight ratio and reducing carbon dioxide emissions. Therefore, the development of advanced gas turbine engines requires the continuous improvement of the service temperature of hot-end components such as combustion chambers, high-pressure guide vanes and high-pressure turbine blades, which promotes the continuous development of superalloys.

Turbine blades are driven by gas and rotate at high speed around the turbine shaft during service. Due to their own weight, significant centrifugal stress will be generated on the blades. Therefore, it is first required that the blade material can withstand stress for a long time at high temperature, that is, it has good high temperature creep resistance. Secondly, the existence of residual oxygen in the gas requires the blade material to have good high temperature oxidation resistance; long-term high temperature action requires the blade material to have good microstructure stability, that is, the brittle TCP phase that reduces the high temperature strength will not be precipitated. In addition, the important physical and mechanical properties of blade materials include density, thermal corrosion resistance, fatigue resistance, etc.

From a microstructural point of view, superalloys manufactured by deformation or conventional casting are composed of grains of different crystal orientations, with grain boundaries between the grains. Compared with the inside of the grain, the grain boundary is actually a crystal plane defect, and its atoms are very seriously dislocated, with a higher density of vacancies and dislocations. Under the action of high temperature thermal activation, the grain boundary is prone to obvious softening, and its bonding strength is significantly lower than that of the grain interior. Therefore, when subjected to load at high temperature, the grain boundary (transverse grain boundary) perpendicular to the load direction is more likely to become a crack initiation or crack propagation channel, resulting in a significant reduction in the high temperature strength of the material.

After the lateral grain boundaries are eliminated by the directional solidification process, the high-temperature strength of the nickel-based superalloy can be significantly improved, and the directional solidification superalloy is developed; after the grain boundaries are completely eliminated by the single crystal process, the single crystal high temperature alloy. Due to the absence of grain boundaries, the addition of grain boundary strengthening elements such as C, B, Zr and Hf is greatly reduced in single crystal superalloys. After limiting the content of these elements, the melting point of the alloy has been greatly increased, so a higher temperature solution heat treatment can be used to completely eliminate the as-cast structure formed during solidification, and obtain a fine and uniform distribution of precipitation phases, thereby increasing the high temperature of the alloy again. strength.

On the basis of the single crystal process, it was found that the addition of Re element can significantly improve the high temperature creep resistance of the alloy, which is mainly attributed to the fact that Re element significantly reduces the element diffusion at high temperature and suppresses the coarsening of the precipitated phase. Nickel-based single crystal superalloys used in the manufacture of high-pressure turbine blades today generally contain Re. According to the content of Re, nickel-based single crystal superalloys are usually divided into the first generation (without Re), the second generation (about 3 wt% Re), the third generation (about 6 wt% Re) and the fourth generation (about 3 wt% Re). 4wt% Re and 4wt% Ru) alloy. However, Re is an extremely rare metal element and its price is extremely high, which has led to a substantial increase in the manufacturing cost of Re-containing alloys and the risk of disruption of the supply chain of Re elements. Therefore, the development of nickel-based single crystal superalloys must pay attention to reducing the content of Re in the alloy, or even not adding Re.

However, although the existing nickel-based single crystal superalloys AM3, CMSX-2 and RenéN4 do not contain Re, their high temperature creep strength is significantly lower than that of CMSX-4 and RenéN5 alloys containing 3 wt% Re.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is to provide a nickel-based alloy. The nickel-based alloy provided by the present application can achieve a good balance in terms of alloy density, alloy cost, microstructure stability, high temperature strength, etc., and has excellent comprehensive performance.

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

5.5wt% to 6.5wt% of aluminum;

5.0wt%～7.0wt% of chromium;

5.0wt% to 7.0wt% of cobalt;

5.5wt%～7.5wt% of molybdenum;

3.0wt%～5.0wt% of tungsten;

0.0wt% to 1.0wt% of titanium;

6.0wt%～8.0wt% of tantalum;

0.0wt% to 0.25wt% of hafnium;

0.0wt% to 0.05wt% of carbon;

0.0wt% to 0.01wt% of boron;

balance of nickel.

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

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

Preferably, the content of the cobalt is 5.9wt%-6.5wt%.

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

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

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

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

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

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

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

The present application also provides a method for preparing the nickel-based alloy, comprising the following steps:

A) prepare a nickel-based master alloy ingot according to the composition ratio;

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

C) heat treatment of the nickel-based alloy casting to obtain a nickel-based alloy.

Preferably, the nickel-based alloy castings include equiaxed crystal castings prepared by investment casting, columnar crystal castings prepared by Bridgman method orientational solidification, or single crystal castings prepared by Bridgeman method orientational solidification.

Preferably, the heat treatment is specifically:

The nickel-based alloy castings are subjected to solution treatment at 1280-1340°C for 2-12 hours, followed by air cooling; then high-temperature aging treatment is performed at 1050-1150°C for 2-8 hours, followed by air-cooling; then at 850-950°C for 12 hours A low-temperature aging treatment of ~20h, followed by air cooling, finally obtains a nickel-based alloy with a uniform structure.

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

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

The application provides a nickel-based alloy, which is composed of the following elements: 5.5wt%～6.5wt% of aluminum; 5.0wt%～7.0wt% of chromium; 5.0wt%～7.0wt% of cobalt; 5.5wt%～ 7.5wt% molybdenum; 3.0wt%～5.0wt% tungsten; 0.0wt%～1.0wt% titanium; 6.0wt%～8.0wt% tantalum; 0.0wt%～0.25wt% hafnium; 0.0wt%～ 0.05wt% carbon; 0.0wt%-0.01wt% boron; balance nickel. In the nickel-based alloy of the present application, the above-mentioned Al content can promote the precipitation of about 55-70% volume fraction of γ′-Ni ₃ Al precipitation phase in the alloy, and at the same time ensure the continuity of the Al ₂ O ₃ film formed on the surface of the alloy at high temperature ; Appropriate content of Cr can avoid the precipitation of TCP phase, and is conducive to the addition of solid solution strengthening elements, which is conducive to improving the high temperature strength of the alloy; Co can form a continuous replacement solid solution in nickel, reducing the stacking fault energy of the γ matrix phase, And to a certain extent, the solidus temperature of the alloy and the dissolution temperature of the γ' phase are increased; thus, the nickel-based alloy provided by this application can increase the total content of Mo, W and Ta, and add a variety of alloying elements and control their content. On the basis of no Re and an appropriate amount of tungsten, the nickel-based alloy achieves a good balance in alloy density, alloy cost, microstructure stability and high temperature strength, and has excellent comprehensive properties.

Description of drawings

Fig. 1 is the preparation flow chart of nickel-based alloy provided by the present invention;

2 is a bar chart of the cost comparison between nickel-based alloys provided in an embodiment of the present invention and alloys in the prior art;

Fig. 3 is the density contrast bar chart of the nickel-based alloy provided by the embodiment of the present invention and the alloy in the prior art;

4 is a bar graph comparing the average electron vacancy number Nv of the nickel-based alloy provided by the embodiment of the present invention and the alloy in the prior art;

5 is a bar graph comparing the average d orbital energy level Md of the nickel-based alloy provided by the embodiment of the present invention and the alloy in the prior art;

6 is a bar graph comparing thermodynamic parameters and structural parameters of nickel-based alloys provided in an embodiment of the present invention and alloys in the prior art;

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

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

Aiming at the problem that the nickel-based alloy does not contain Re in the prior art, but the high-temperature creep strength is not high, the present invention provides a nickel-based alloy, which develops a different kind of nickel-based alloy by balancing the strengthening effect of the alloy elements. Re-containing, but the high-temperature strength, especially the high-temperature creep strength, is close to the nickel-based single crystal superalloy containing Re, and other important properties are taken into account, such as good phase stability and oxidation resistance. Specifically, the nickel-based superalloy described in this application is composed of the following elements:

5.5wt% to 6.5wt% of aluminum;

5.0wt%～7.0wt% of chromium;

5.0wt% to 7.0wt% of cobalt;

5.5wt%～7.5wt% of molybdenum;

3.0wt%～5.0wt% of tungsten;

0.0wt% to 1.0wt% of titanium;

6.0wt%～8.0wt% of tantalum;

0.0wt% to 0.25wt% of hafnium;

0.0wt% to 0.05wt% of carbon;

0.0wt% to 0.01wt% of boron;

balance of nickel.

In the nickel-based alloy of the present application, aluminum (Al) is the main element forming the γ' phase, which brings a significant precipitation strengthening effect to the alloy. In addition, Al element is easy to form a dense Al ₂ O ₃ film on the surface of the alloy at high temperature, which hinders the diffusion of oxygen element into the alloy, thereby improving the oxidation resistance of the alloy. The aluminum content described in this application is 5.5wt% to 6.5wt%, and the aluminum within this content range can promote the precipitation of about 55-70% volume fraction of γ'-Ni ₃ Al precipitate in the alloy, and at the same time ensure the surface of the alloy at high temperature. The continuity of the Al ₂ O ₃ film is generated. In some specific embodiments, the content of the aluminum is 5.6 wt % to 6.3 wt %; in some specific embodiments, the content of the aluminum is 5.7 wt % to 6.2 wt %.

Chromium (Cr) is mainly segregated in the γ matrix phase and plays a small amount of solid solution strengthening; Cr itself has high oxidation resistance and hot corrosion resistance, and its presence can also promote the formation of Al ₂ O ₃ film at high temperature, It can improve the oxidation resistance of the alloy; but too high Cr content leads to the easy precipitation of TCP phase in the alloy, and limits the addition of strong solid solution strengthening elements such as Re, W and Mo, which is not conducive to the high temperature strength of the alloy. After adjustment, the content of chromium in this application is 5.0wt% to 7.0wt%; in some specific embodiments, the content of chromium is 5.2wt% to 6.8wt%; The content of chromium is 5.8wt%-6.2wt%.

Cobalt (Co) can form a continuous substitutional solid solution in nickel, reduce the stacking fault energy of the γ matrix phase, and increase the solidus temperature of the alloy and the dissolution temperature of the γ' phase to a certain extent; but Co has less resources than Ni. , and the price is high, and excessive Co also easily leads to the formation of TCP phase. After adjustment, the content of cobalt described in this application is 5.0 wt % to 7.0 wt %; in some specific embodiments, the content of cobalt is 5.9 wt % to 6.5 wt %; The content of cobalt is 6.0 wt % to 6.2 wt %.

Molybdenum (Mo) is mainly segregated in the γ matrix phase, which plays a significant 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 alleviate the adverse effect of the addition of refractory elements on the alloy density. However, Mo itself has poor oxidation resistance and hot corrosion resistance, and too high Mo content can easily promote the precipitation of TCP phase. After adjustment, the molybdenum content in the present application is 5.5wt% to 7.5wt%; in some specific embodiments, the molybdenum content is 6wt% to 7wt%; in some specific embodiments, the molybdenum content The content is 6.3wt% to 6.7wt%.

The strengthening behavior of tungsten (W) is very similar to that of Mo, and it is mainly segregated in the γ matrix phase, but W has a lower diffusion rate than Mo, which can effectively reduce the coarsening rate of the γ' phase and increase the creep life. In the absence of Re, W is the most important solid solution strengthening element, which can partially replace the strengthening effect of Re, but too high W will also cause the alloy to easily precipitate TCP phase. After adjustment, the content of tungsten described in this application is 3.0wt% to 5.0wt%; in some specific embodiments, the content of tungsten is 3.2wt% to 4.8wt%; The content of the tungsten is 3.6wt%-3.9wt%.

Titanium (Ti) is mainly segregated in the γ' phase, which can replace the position of Al to form more γ' phase, which plays a role in precipitation strengthening. Compared with Al, Ti can more effectively increase the solution temperature of γ' phase and the lattice constant of γ' phase, and provide additional strengthening effect by increasing the anti-phase boundary energy of γ' phase. However, excessive Ti is detrimental to the castability of the alloy and causes an increase in the segregation of Cr and Mo in the γ phase, thereby increasing the risk of the alloy to precipitate TCP phase. After adjustment, the content of titanium described in this application is 0.0wt% to 1.0wt%; in some specific embodiments, the content of titanium is 0.1wt% to 0.8wt%; in some specific embodiments, the The content of titanium is 0.15wt% to 0.35wt%.

The role of tantalum (Ta) in single crystal superalloys is similar to that of Ti, and it is mainly segregated in the γ' phase, which increases the volume fraction of the γ' phase, but has a higher high-temperature strengthening effect relative to the Ti element, which can significantly improve the γ' of the alloy. Solution temperature, solidus temperature, tensile strength and creep resistance of the 'phase. However, compared with other alloying elements, Ta itself is a relatively noble metal and has a high density. Too high Ta results in a substantial increase in alloy density and cost. After adjustment, the content of tantalum in this application is 6.0wt% to 8.0wt%; in some specific embodiments, the content of tantalum is 6.5wt% to 7.1wt%; in some specific embodiments, the The content of the tantalum is 6.8wt%-7.0wt%.

Hafnium (Hf) exists as a trace element in single crystal superalloys. A small amount of Hf can effectively adsorb the harmful impurity element S in the alloy, thereby increasing the strength and toughness of the alloy, and at the same time, it can also increase the adhesion of the coating, thereby improving the environmental resistance of the alloy. However, Hf can significantly reduce the melting point of the alloy and reduce the heat treatment window of the alloy. After adjustment, the hafnium content described in this application is 0.0wt% to 0.25wt%; in some specific embodiments, the hafnium content is 0.05wt% to 0.20wt%; The content of hafnium is 0.08wt%-0.12wt%.

Carbon (C) and boron (B) elements also exist in the form of trace elements in single crystal superalloys. They tend to segregate at the subgrain boundary of the alloy, and form carbides or borides with alloying elements such as Ti, Ta, Mo, W, etc. to strengthen the subgrain boundary, thereby reducing the subgrain boundary cracking tendency of the alloy; but C and B Can significantly reduce the melting point of the alloy. After adjustment, the carbon content in the present application is 0.0wt% to 0.05wt%; the boron content is 0.0wt% to 0.01wt%. In some specific embodiments, the content of the carbon is 0.02wt% to 0.04wt%; the content of the boron is 0.002wt% to 0.004wt%.

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

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

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

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

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

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

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

The present application also provides a method for preparing a nickel-based alloy, comprising the following steps:

A) prepare a nickel-based master alloy ingot according to the composition ratio of the above-mentioned nickel-based alloy;

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

C) heat treatment of the nickel-based alloy casting to obtain a nickel-based alloy.

In the above-mentioned preparation method of the nickel-based alloy, the specific composition of the nickel-based master alloy ingot has been described in detail above, and will not be repeated here.

In the above-mentioned process of preparing the nickel-based alloy, the method for preparing the nickel-based master alloy ingot is carried out according to a method well known to those skilled in the art. For example, the present application puts the raw materials into a vacuum melting furnace for melting according to the composition ratio, to obtain nickel-based master alloy ingots.

According to the present invention, the nickel-based master alloy ingot is then remelted, and the remelting is performed in a manner well known in the art. For example, the present application performs the remelting of the nickel-based master alloy ingot in a vacuum device; A nickel-based alloy casting is then prepared. The nickel-based alloy casting can be prepared into a columnar crystal casting by a directional solidification method as required, or a single crystal casting can be prepared by a spiral selection method or a seed crystal method.

In the present application, the nickel-based alloy casting is finally subjected to heat treatment, and the heat treatment can be carried out according to the well-known methods of nickel-based alloys; The cooling steps are carried out in sequence. Specifically, the temperature of the solution treatment is 1280-1340° C. and the time is 2-12 hours. The temperature of the high-temperature aging treatment is 1050-1150° C. and the time is 2-8 hours. The temperature of the aging treatment is 850-950° C., the time is 12-20 h, and the cooling method is air cooling or forced air quenching.

In a specific embodiment, the nickel-based alloy is prepared by vacuum induction melting + directional solidification process, and the preparation flow chart of the method is shown in FIG. , to obtain a master alloy ingot with precisely controlled composition; (2) remelting the ingot material and preparing a single crystal casting or directional casting through a directional solidification process; (3) obtaining a casting of suitable size by machining; (4) by Heat treatment eliminates the as-cast structure in the alloy and obtains the optimal microstructure.

According to embodiments of the present invention, the nickel-based alloys described herein are formed by making articles applicable to gas turbine engines, and more particularly, to gas turbine engine turbine blades composed of The alloy is prepared to obtain: 5.5wt%～6.5wt% of aluminum; 5.0wt%～7.0wt% of chromium; 5.0wt%～7.0wt% of cobalt; 5.5wt%～7.5wt% of molybdenum; 3.0wt%～5.0wt% % tungsten; 0.0wt%～1.0wt% titanium; 6.0wt%～8.0wt% tantalum; 0.0wt%～0.25wt% hafnium; 0.0wt%～0.05wt% carbon; 0.0wt%～0.01wt% % boron; balance nickel.

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

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

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

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

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

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

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

In order to further understand the present invention, the nickel-based alloy provided by the present invention is described in detail below with reference to the examples, and the protection scope of the present invention is not limited by the following examples.

Example

The nickel-based superalloy of the present application achieves a good balance in alloy density, alloy cost, microstructure stability, high temperature strength, etc., and has excellent comprehensive properties. In order to further illustrate the effect of the present application, the present application lists 7 specific examples, and compares 6 of them with 5 existing alloys. The alloy compositions of 7 examples and 5 existing alloy compositions are shown in Table 1; in the examples, the preparation method of the nickel-based superalloy is as follows:

1) put the raw material according to the composition ratio shown in Table 1 into the vacuum induction melting furnace to smelt the alloy, and prepare the mother alloy ingot;

2) Remelting the mother alloy ingot in a vacuum equipment, and then in the mold shell formed by the refractory material, prepare a columnar crystal casting by a directional solidification method, or prepare a single crystal casting by a spiral selection method or a seed crystal method;

3) The casting is subjected to solution treatment at 1280-1340°C for 2-12 hours, and then air-cooled; then subjected to high-temperature aging treatment at 1050-1150°C for 2-8 hours, followed by air-cooling; and then at 850-950°C A low-temperature aging treatment of 12-20h, followed by air cooling, finally obtains a nickel-based superalloy with a uniform structure.

Table 1 Example and the nickel-based superalloy composition data table (wt%) provided by the prior art

1) The cost of the alloy is greatly reduced compared to the alloy containing Re

According to the raw material composition ratio of the alloy and the market price of each raw material in December 2017, the raw material cost of each alloy was calculated. The cost of 6 examples of alloys of the present application and 5 existing alloys are shown in FIG. 2 . It can be seen from Figure 2 that the cost of the 6 examples is reduced by about 76% relative to the CMSX-4 and RenéN5 alloys containing about 3wt%; compared to the AM3, CMSX-2 and RenéN4 alloys without Re, the 6 examples The cost is slightly higher, but at the same level. This shows that the cost of the alloy of the present application is well controlled.

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

Alloy density is one of the main factors that determine the centrifugal stress when the rotating part is working, so it is an element that must be considered in the design. Figure 3 is a bar graph comparing the calculated densities of 6 examples of the alloys of the present application and 5 existing alloys. Due to the use of a large amount of refractory elements W+Mo+Ta to replace the strengthening effect of Re, the density of the alloy in this application is comparable to that of the alloy CMSX-2 without Re, slightly higher than that of the alloy AM3 and RenéN4, but slightly lower than that of the alloy containing Re. Alloys CMSX-4 and RenéN5, thus indicating that the density of the nickel-based alloy of the present application is still controlled within a reasonable range.

3) Has good tissue stability

The alloy of the present application has good microstructure 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 of 6 embodiments of the alloy of the present application and 5 existing alloys according to the PHACOMP method; Fig. 5 is a graph of 6 embodiments of the alloy of the present application and 5 Comparison histogram of the average d orbital energy level Md of the existing alloys; it can be seen from Figure 4 that the Nv values of the alloys of the present application are significantly lower than those of the existing alloys CMSX-2, AM3, RenéN4, CMSX-4 and RenéN5 Calculated value; it can be seen from Figure 5 that the Md value of the alloy of the present application is comparable to that of alloy AM3, significantly lower than that of alloy RenéN4, and slightly higher than the calculated values of alloys CMSX-2, RenéN5 and CMSX-4. To sum up, the nickel-based alloy of the present application has good microstructure stability.

4) Excellent high temperature creep resistance

This application considers the high temperature creep resistance of the alloy from four aspects: (1) the phase transition temperature of the alloy; (2) the degree of solid solution strengthening of the alloy; (3) the number of precipitation strengthening phases of the alloy; (4) the alloy's Lattice mismatch.

The three important phase transition temperatures of nickel-based superalloys are: ① the solid solution temperature of the γ' phase, that is, the critical temperature at which the γ' phase is completely dissolved into the γ phase as the temperature increases; ② the solidus temperature, that is, as the temperature increases , the critical temperature at which the alloy begins to melt; ③ the liquidus temperature, that is, the critical temperature at which the alloy completely melts as the temperature increases. The higher the γ' phase solution temperature, the more undissolved γ' phase at high temperature, and the higher the high temperature precipitation strengthening effect of the alloy; the higher the solidus and liquidus temperatures, the higher the temperature resistance of the alloy itself. . Fig. 6(a) is a bar graph comparing the calculated values of the γ' phase solution temperature, solidus temperature and liquidus temperature of 6 examples of the alloy of the present application and 5 existing alloys, from Fig. 6(a) ), it can be seen that the solid solution temperature of the γ' phase of the six embodiments of the alloy of the present application is comparable to that of the alloys CMSX-2, AM3, and CMSX-4, higher than that of the alloy RenéN4, and slightly lower than that of the alloy RenéN5; The wire temperature is comparable to alloys CMSX-2, AM3, CMSX-4 and RenéN5, and slightly higher than alloy RenéN4.

The solid solution strengthening degree of the alloy mainly examines the effect of three strong solid solution strengthening elements Re, W and Mo. This application uses a solid solution strengthening factor _ISSS to evaluate the degree of solid solution strengthening of the alloy. The higher the _ISSS , the higher the degree of solid solution strengthening of the alloy. Figure 6(b) is a bar graph comparing the calculated values of the _ISSS of 6 examples of the alloy of the application and 5 existing alloys. It can be seen from Figure 6(b) that due to the addition of a large amount of W and Mo, the The ISSS of the examples is significantly higher than the calculated values of alloys CMSX-2, _RenéN4 and AM3, and is at the same level as the calculated values of alloys CMSX-4 and RenéN5.

The degree of precipitation strengthening of the alloy mainly examines the fraction of γ' phase in the alloy at the service temperature. The higher the value, the greater the potential of the alloy's precipitation strengthening. Figure 6(c) is a bar graph comparing the mole fractions of γ' phase at 850°C, 900°C, 1050°C and 1100°C for the six examples of the alloy of the present application and five existing alloys, respectively, calculated by Thermo-Calc ; It can be seen from Fig. 6(c) that at the same temperature, the mole fraction of γ' phase in all six examples is not lower than the corresponding values of alloys RenéN4, CMSX-4 and RenéN5, which are comparable to alloys CMSX-2 and AM3 .

Another key parameter related to alloy creep strength is the degree of lattice mismatch of the γ/γ′ phase. Studies have shown that the lattice mismatch degree is negative, and the higher the absolute value is, it is beneficial to increase the creep strength, but the excessively high mismatch degree will lead to the instability of the two-phase coherent structure of γ/γ′, and the loss of Coherence enhancement effect. It is generally believed that the degree of lattice mismatch should not be higher than 0.5%. Fig. 6(d) is a bar graph comparing the calculated values of lattice mismatch degrees of 6 examples of the alloy of the present application and 5 existing alloys. It can be seen from Fig. 6(d) that the The degree of distribution is negative, and its absolute value is higher than the calculated value of alloys CMSX-2, AM3, RenéN4, CMSX-4 and RenéN5, but lower than 0.5%.

5) Observe the microstructure and durability of Example 7

As shown in FIG. 7 , FIG. 7 is a photo of the microstructure of the nickel-based alloy prepared in Example 7, and Table 2 is the durable performance data table of the nickel-based alloy prepared in Example 7;

Table 2 Durable performance data table of the nickel-based alloy prepared in Example 7

Test Conditions Persistent life, h Elongation, % rate of reduction in area,% 850℃/650MPa 24.3 twenty three 34 982℃/248MPa 27.6 31 48 1040℃/145MPa 67.6 14 49

The manufactured articles formed of the nickel-based alloys prepared in the above examples, which are specifically applied to turbine blades of gas turbine engines, also have the same properties as the above-mentioned nickel-based alloys.

The descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments enables 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 implemented in 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 (16)

1. A nickel-based alloy consisting of the following elements: 5.5wt% to 6.5wt% of aluminum; 5.0wt%～7.0wt% of chromium; 5.0wt% to 7.0wt% of cobalt; 5.5wt%～7.5wt% of molybdenum; 3.0wt%～5.0wt% of tungsten; 0.0wt% to 1.0wt% of titanium; 6.0wt%～8.0wt% of tantalum; 0.0wt% to 0.25wt% of hafnium; 0.0wt% to 0.05wt% of carbon; 0.0wt% to 0.01wt% of boron; balance of nickel. 2 . The nickel-based alloy according to claim 1 , wherein the content of the aluminum is 5.7 wt % to 6.2 wt %. 3 . 3 . The nickel-based alloy according to claim 1 , wherein the content of the chromium is 5.2 wt % to 6.8 wt %. 4 . 4 . The nickel-based alloy according to claim 1 , wherein the content of the cobalt is 5.9 wt % to 6.5 wt %. 5 . 5 . The nickel-based alloy according to claim 1 , wherein the content of the molybdenum is 6.0 wt % to 7.0 wt %. 6 . 6 . The nickel-based alloy according to claim 1 , wherein the content of the tungsten is 3.2 wt % to 4.8 wt %. 7 . 7 . The nickel-based alloy according to claim 1 , wherein the content of the titanium is 0.1 wt % to 0.8 wt %. 8 . 8 . The nickel-based alloy according to claim 1 , wherein the content of the tantalum is 6.5 wt % to 7.1 wt %. 9 . 9. The nickel-based alloy of claim 1, comprising the following elements: 5.95wt% aluminum, 5.8wt% chromium, 6.2wt% cobalt, 6.5wt% molybdenum, 3.7wt% Tungsten, 0.15wt% titanium, 7wt% tantalum and balance nickel. 10. The nickel-based alloy of claim 1, comprising the following elements: 5.95wt% aluminum, 5.8wt% chromium, 6wt% cobalt, 6.4wt% molybdenum, 3.8wt% tungsten , 0.15wt% titanium, 7wt% tantalum and balance nickel. 11. The nickel-based alloy of claim 1, comprising the following elements: 6.03wt% aluminum, 6.0wt% chromium, 6.2wt% cobalt, 6.5wt% molybdenum, 3.72wt% Tungsten, 0.22wt% titanium, 6.8wt% tantalum, 0.09wt% hafnium, 0.03wt% carbon, 0.003wt% boron with balance nickel. 12. The preparation method of the nickel-based alloy according to any one of claims 1 to 11, comprising the following steps: A) prepare a nickel-based master alloy ingot according to the composition ratio; B) remelting the nickel-based master alloy ingot, and then preparing the nickel-based alloy casting; C) heat treatment of the nickel-based alloy casting to obtain a nickel-based alloy. 13 . The preparation method according to claim 12 , wherein the nickel-based alloy castings comprise equiaxed crystal castings prepared by investment casting, columnar crystal castings prepared based on Bridgman method orientational solidification, or Single crystal castings prepared by Bridgman method directional solidification. 14. preparation method according to claim 12, is characterized in that, described heat treatment is specifically: The nickel-based alloy castings were solution treated at 1280-1340°C for 2-12 hours, followed by air cooling; then subjected to high-temperature aging treatment at 1050-1150°C for 2-8 hours, followed by air cooling; and then performed at 850-950°C for 12 hours. A low-temperature aging treatment of ~20h, followed by air cooling, finally obtains a nickel-based alloy with a uniform structure. 15. A manufactured article applied to a gas turbine engine, prepared from the nickel-based alloy according to any one 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.

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