Nickel-based single crystal alloy, method for producing same, use thereof and heat treatment method

文档序号：527560 发布日期：2021-06-01 浏览：33次中文

阅读说明：本技术 镍基单晶合金、其制备方法、用途和热处理方法 (Nickel-based single crystal alloy, method for producing same, use thereof and heat treatment method ) 是由赵云松杨振宇张辉刘培元骆宇时张剑于 2021-01-13 设计创作，主要内容包括：本发明公开了一种镍基单晶合金、其制备方法、用途和热处理方法。该镍基单晶合金各组分重量百分比的取值范围包括：Cr：2％～4％；Al：5.55％～5.95％；Ta：8％～10％；Co：7％～10％；Mo：1％～2.5％；Re：5.5％～7％；W：4.5％～6.5％；Nb：0.4～0.6％；Ti：0.005～0.015％；C：0.006～0.015％；Hf：0.2％～0.5％；B：0.005～0.015％；Y：0.005～0.02％,La：0.005～0.02％,Si：0.005～0.1％,其余为Ni。通过该制备方法能够制备得到该合金。该合金能够用于制备单晶试棒和/或单晶涡轮叶片。该单晶试棒和/或单晶涡轮叶片由该合金制备得到,单晶试棒和/或单晶涡轮叶片能够制备得到该单晶试棒和/或单晶涡轮叶片。该合金可满足高推重比航空发动机涡轮叶片的需要。(The invention discloses a nickel-based single crystal alloy, a preparation method, application and a heat treatment method thereof. The value ranges of the nickel-based single crystal alloy comprise the following components in percentage by weight: cr: 2% -4%; al: 5.55 to 5.95 percent; ta: 8% -10%; co: 7 to 10 percent; mo: 1% -2.5%; re: 5.5% -7%; w: 4.5% -6.5%; nb: 0.4-0.6%; ti: 0.005-0.015%; c: 0.006-0.015%; hf: 0.2 to 0.5 percent; b: 0.005-0.015%; y: 0.005-0.02%, La: 0.005-0.02%, Si: 0.005-0.1% and the balance of Ni. The alloy can be prepared by the preparation method. The alloy can be used for preparing single crystal test rods and/or single crystal turbine blades. The single crystal test bar and/or the single crystal turbine blade is/are prepared from the alloy, and the single crystal test bar and/or the single crystal turbine blade can be prepared from the single crystal test bar and/or the single crystal turbine blade. The alloy can meet the requirement of high thrust-weight ratio aeroengine turbine blades.)

1. The nickel-based single crystal alloy is characterized in that the value ranges of the weight percentages of the components comprise: cr: 2% -4%; al: 5.55 to 5.95 percent; ta: 8% -10%; co: 7 to 10 percent; mo: 1% -2.5%; re: 5.5% -7%; w: 4.5% -6.5%; nb: 0.4-0.6%; ti: 0.005-0.015%; c: 0.006-0.015%; hf: 0.2 to 0.5 percent; b: 0.005-0.015%; y: 0.005-0.02%, La: 0.005-0.02%, Si: 0.005-0.1% and the balance of Ni.

2. The method for producing the nickel-based single crystal alloy according to claim 1, comprising the steps of:

taking Ni, W, Cr, Ta, Co, Mo, Nb and Re according to the weight percentage of the components in the claim 1 to obtain a first mixture;

heating the first mixture under vacuum condition to be completely melted to obtain a melted first mixture;

refining the molten first mixture to obtain a first alloy liquid; wherein, in the refining process, the refining temperature is 1590 +/-10 ℃, and the refining duration is 30-60 min;

the first alloy liquid is formed into a film to obtain the first alloy liquid after the film is formed;

adding metallic Al to the first alloy liquid after the film is formed according to the weight ratio of the components in the claim 1 to obtain a second mixture;

obtaining a second alloy liquid after Al in the second mixture is completely melted;

the second alloy liquid is formed into a film to obtain second alloy liquid after the film is formed;

adding metals C, B, Hf, Ti, La, Y and Ce to the second alloy liquid according to the weight ratio of the components in the claim 1 to obtain a third mixture;

obtaining a third alloy liquid after the metals C, B, Hf, Ti, La, Y and Ce are completely melted;

and when the temperature of the third alloy liquid is reduced to a temperature range of 1480 +/-20 ℃, casting to obtain the nickel-based single crystal alloy ingot.

3. The method for preparing the nickel-based single crystal alloy according to claim 2, wherein the preparation of the nickel-based single crystal alloy is performed in a vacuum induction furnace, and a value of a vacuum pressure in the vacuum induction furnace ranges from 0.01Pa to 10 Pa.

4. The method for producing the nickel-based single-crystal alloy according to claim 2, wherein the ingot is cylindrical in shape, the diameter of the cylinder is 90mm, and the length of a generatrix of the cylinder is 100 mm.

5. The preparation method of the nickel-based single crystal alloy according to claim 2, wherein after the third alloy liquid is cooled to a temperature range of 1480 ± 20 ℃ in the step, casting is performed to obtain the nickel-based single crystal alloy ingot, and the method further comprises the following steps:

and sequentially polishing, removing oxide skin and cutting the nickel-based single crystal alloy ingot.

6. The method for preparing a nickel-based single crystal alloy according to claim 2, wherein the step of adding metallic Al to the first alloy liquid after film formation is performed by a charging device of a vacuum induction furnace.

7. Use of the nickel base single crystal alloy according to claim 1 for the production of single crystal test rods and/or single crystal turbine blades.

8. The method for heat-treating a nickel-base single crystal alloy according to claim 1, comprising the steps of:

placing the nickel-based single crystal alloy casting of claim 1 into a heat treatment furnace, heating to 1300 +/-5 ℃, and preserving heat for 1-4 h; continuously heating to 1310 +/-5 ℃, and preserving the temperature for 1-4 h; continuously heating to 1320 +/-5 ℃, and keeping the temperature for 1-4 h; continuously heating to 1330 +/-5 ℃, and preserving the temperature for 1-4 h; continuously heating to 1335 +/-5 ℃, preserving the temperature for 4-13 h, taking out and air-cooling to room temperature to obtain the nickel-based single crystal alloy after solution treatment;

primary aging treatment: putting the nickel-based single crystal alloy after the solution treatment into a heat treatment furnace, heating to 1150 +/-10 ℃, preserving the heat for 4-10 h, taking out, air-cooling to room temperature, and obtaining the nickel-based single crystal alloy after the primary aging treatment;

secondary aging treatment: putting the nickel-based single crystal alloy casting subjected to the primary aging treatment into a heat treatment furnace, heating to 870 +/-10 ℃, preserving the temperature for 24-36 h, taking out, and air-cooling to room temperature.

9. A single crystal test rod and/or a single crystal turbine blade prepared from the nickel-based single crystal alloy of claim 1.

10. A method for producing a single crystal test rod and/or a single crystal turbine blade as claimed in claim 9,

placing the nickel-based single crystal alloy ingot according to claim 2 in a crucible and in a directional solidification furnace;

heating the nickel-based single crystal alloy ingot in the crucible to be molten to obtain molten nickel-based single crystal alloy;

refining the melted nickel-based single crystal alloy for 10-20 min at the temperature of 1550-1580 ℃ to obtain the refined nickel-based single crystal alloy;

when the temperature of the refined nickel-based single crystal alloy is reduced to 1530-1550 ℃, pouring to obtain alloy liquid after pouring;

and (3) keeping the temperature of the alloy liquid after the pouring in a mould shell for 8-15 min, and drawing at a drawing speed of 2.5-6 mm/min to prepare the single crystal test bar and/or the single crystal turbine blade.

Technical Field

The invention relates to the technical field of metallurgy, in particular to a nickel-based single crystal alloy, a preparation method, application and a heat treatment method thereof.

Background

The nickel-based single crystal alloy has excellent comprehensive properties of high-temperature creep resistance, fatigue resistance, oxidation resistance, hot corrosion resistance and the like, so that the nickel-based single crystal alloy is widely applied to blade parts of aeroengines and industrial gas turbines with high thrust-weight ratios. The nickel-based single crystal alloy eliminates crystal boundaries, does not generate crystal boundary fracture easily caused by polycrystalline materials, has greatly improved strength compared with isometric crystals and oriented columnar crystals, and has great superiority in improving the strength and prolonging the service life of turbine blades. Since the first generation of single crystals appeared in the 20 th century and the 80 th generation, single crystal superalloys have been developed to the fifth generation, foreign nickel-based single crystal alloys have been developed to the fifth generation, domestic mature development to the second generation, and the third and fourth generations are under preliminary study. At present, the nickel-based single crystal alloy blade is completely finished in China and is two generations abroad, and the loss of high-performance materials becomes an important factor for limiting the development of the aeroengine in China.

Disclosure of Invention

In view of the above, the invention provides a nickel-based single crystal alloy, a preparation method, an application and a heat treatment method thereof, which have excellent tensile strength, endurance strength, fatigue property, better high-temperature oxidation resistance and hot corrosion resistance, and better casting manufacturability, and can meet the requirements of high thrust-weight ratio aeroengine turbine blades, thereby being more practical.

In order to achieve the first object, the technical scheme of the nickel-based single crystal alloy provided by the invention is as follows:

the nickel-based single crystal alloy provided by the invention comprises the following components in percentage by weight: cr: 2% -4%; al: 5.55 to 5.95 percent; ta: 8% -10%; co: 7 to 10 percent; mo: 1% -2.5%; re: 5.5% -7%; w: 4.5% -6.5%; nb: 0.4-0.6%; ti: 0.005-0.015%; c: 0.006-0.015%; hf: 0.2 to 0.5 percent; b: 0.005-0.015%; y: 0.005-0.02%, La: 0.005-0.02%, Si: 0.005-0.1% and the balance of Ni.

In order to achieve the second object, the technical scheme of the preparation method of the nickel-based single crystal alloy provided by the invention is as follows:

the preparation method of the nickel-based single crystal alloy provided by the invention comprises the following steps:

according to the weight percentage of the components of the nickel-based single crystal alloy provided by the invention, taking metal Ni, W, Cr, Ta, Co, Mo, Nb and Re to obtain a first mixture;

heating the first mixture under vacuum condition to be completely melted to obtain a melted first mixture;

refining the molten first mixture to obtain a first alloy liquid; wherein, in the refining process, the refining temperature is 1590 +/-10 ℃, and the refining duration is 30-60 min;

the first alloy liquid is formed into a film to obtain the first alloy liquid after the film is formed;

according to the weight ratio of the components of the nickel-based single crystal alloy, adding metal Al into the first alloy liquid after film forming to obtain a second mixture;

obtaining a second alloy liquid after Al in the second mixture is completely melted;

the second alloy liquid is formed into a film to obtain second alloy liquid after the film is formed;

adding metals C, B, Hf, Ti, La, Y and Ce into the second alloy liquid according to the weight ratio of the components of the nickel-based single crystal alloy to obtain a third mixture;

obtaining a third alloy liquid after the metals C, B, Hf, Ti, La, Y and Ce are completely melted;

and when the temperature of the third alloy liquid is reduced to a temperature range of 1480 +/-20 ℃, casting to obtain the nickel-based single crystal alloy ingot.

The preparation method of the nickel-based single crystal alloy provided by the invention can be further realized by adopting the following technical scheme.

Preferably, the preparation of the nickel-based single crystal alloy is completed in a vacuum induction furnace, and the value range of the vacuum pressure in the vacuum induction furnace is 0.01Pa-10 Pa.

Preferably, the nickel-based single crystal alloy ingot is cylindrical, the diameter of the cylinder is phi 90mm, and the length of a generatrix of the cylinder is 100 mm.

Preferably, after the third alloy liquid is cooled to a temperature range of 1480 ± 20 ℃ in the step, casting is performed to obtain the nickel-based single crystal alloy ingot, and the method further comprises the following steps:

and sequentially polishing, removing oxide skin and cutting the nickel-based single crystal alloy ingot.

Preferably, the step of adding metallic Al to the first alloy liquid after film formation is performed by a feeding device of a vacuum induction furnace.

In order to achieve the third object, the technical scheme of the application of the nickel-based single crystal alloy provided by the invention is as follows:

the invention provides application of a nickel-based single crystal alloy in preparing a single crystal test rod and/or a single crystal turbine blade.

In order to achieve the fourth object, the present invention provides a heat treatment method for a nickel-based single crystal alloy, comprising:

putting the casting of the nickel-based single crystal alloy into a heat treatment furnace, heating to 1300 +/-5 ℃, and preserving heat for 1-4 hours; continuously heating to 1310 +/-5 ℃, and preserving the temperature for 1-4 h; continuously heating to 1320 +/-5 ℃, and keeping the temperature for 1-4 h; continuously heating to 1330 +/-5 ℃, and preserving the temperature for 1-4 h; continuously heating to 1335 +/-5 ℃, preserving the temperature for 4-13 h, taking out and air-cooling to room temperature to obtain the nickel-based single crystal alloy after solution treatment;

primary aging treatment: putting the nickel-based single crystal alloy casting subjected to the solution treatment into a heat treatment furnace, heating to 1150 +/-10 ℃, preserving the heat for 4-10 h, taking out and air-cooling to room temperature to obtain the nickel-based single crystal alloy subjected to primary aging treatment;

In order to achieve the fifth object, the present invention provides a single crystal test rod and/or a single crystal turbine blade, wherein:

the single crystal test rod and/or the single crystal turbine blade provided by the invention are/is prepared from the nickel-based single crystal alloy provided by the invention.

In order to achieve the sixth object, the technical solution of the method for manufacturing a single crystal test rod and/or a single crystal turbine blade according to the present invention is as follows:

putting the nickel-based single crystal alloy ingot provided by the invention into a crucible and placing the crucible into a directional solidification furnace;

heating the nickel-based single crystal alloy ingot in the crucible to be molten to obtain molten nickel-based single crystal alloy;

refining the melted nickel-based single crystal alloy for 10-20 min at the temperature of 1550-1580 ℃ to obtain the refined nickel-based single crystal alloy;

when the temperature of the refined nickel-based single crystal alloy is reduced to 1530-1550 ℃, pouring to obtain alloy liquid after pouring;

The beneficial effects of the invention include:

1. the nickel-based single crystal alloy material obtained by the method has higher tensile, lasting and fatigue properties.

2. The nickel-based single crystal alloy material obtained by the method has the advantages of good casting performance, high tolerance of casting grain boundary defects and low content of micro-porosity.

3. The nickel-based single crystal alloy provided by the invention has a wide heat treatment window and is easy to control the solution treatment.

4. The nickel-based single crystal alloy provided by the invention has the advantages of simple heat treatment process, short heat treatment time, greatly reduced heat treatment cost and contribution to practical engineering application.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic diagram of a high-power microstructure of a nickel-based single crystal alloy provided by an embodiment of the invention;

FIG. 2 is a schematic diagram of a low power porosity distribution of a nickel-based single crystal alloy provided by an embodiment of the invention;

FIG. 3 is a schematic diagram of a twin crystal preparation of a nickel-based single crystal alloy according to an embodiment of the present invention;

FIG. 4 is a schematic representation of a sample after macro-etching of a nickel-based single crystal alloy provided by an embodiment of the present invention;

FIG. 5 is a graph of endurance and grain boundary angle of the nickel-based single crystal alloy at 1100 deg.C/140 MPa according to the present invention. FIG. 5(a) is a graph showing the relationship between the endurance property and the grain boundary angle of the nickel-based single crystal alloy provided in example 1 of the present invention at 1100 ℃/140 MPa; FIG. 5(a) is a graph of endurance and grain boundary angle of a Ni-based single crystal alloy at 1100 deg.C/140 MPa according to example 1 of the present invention; FIG. 5(b) is a graph of endurance and grain boundary angle of the Ni-based single crystal alloy provided in example 2 of the present invention at 1100 deg.C/140 MPa; FIG. 5(c) is a graph of endurance and grain boundary angle of the Ni-based single crystal alloy provided in example 3 of the present invention at 1100 deg.C/140 MPa; FIG. 5(d) is a graph of endurance and grain boundary angle of the Ni-based single crystal alloy provided in example 4 of the present invention at 1100 deg.C/140 MPa; FIG. 5(e) is a graph of endurance and grain boundary angle of the Ni-based single crystal alloy at 1100 deg.C/140 MPa according to example 5 of the present invention; FIG. 5(f) is a graph of the endurance behavior of nickel of the comparative alloy Rene N6 at 1100 deg.C/140 MPa as a function of grain boundary angle;

FIG. 6 is a schematic diagram showing the relationship between the change of materials during the preparation of the nickel-based single crystal alloy according to the embodiment of the present invention.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description will be made on a nickel-based single crystal alloy, a method for preparing the same, use thereof, a heat treatment method thereof, a single crystal test bar, a single crystal turbine blade, and methods for preparing the same according to the present invention, and specific embodiments, structures, features, and effects thereof, with reference to the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "an embodiment" refers to not necessarily the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, with the specific understanding that: both a and B may be included, a may be present alone, or B may be present alone, and any of the three cases can be provided.

Nickel-based single crystal alloy

The nickel-based single crystal alloy provided by the invention comprises the following components in percentage by weight: cr: 2% -4%; al: 5.55 to 5.95 percent; ta: 8% -10%; co: 7 to 10 percent; mo: 1% -2.5%; re: 5.5% -7%; w: 4.5% -6.5%; nb: 0.4-0.6%; ti: 0.005-0.015%; c: 0.006-0.015%; hf: 0.2 to 0.5 percent; b: 0.005-0.015%; y: 0.005-0.02%, La: 0.005-0.02%, Si: 0.005-0.1% and the balance of Ni.

The chemical composition design of the nickel-based alloy provided by the invention is mainly based on the following reasons:

re is one of important strengthening alloys in the nickel-based single crystal alloy, and the initial melting point of the alloy is improved. Re is mainly distributed in a gamma matrix, can block the movement of dislocation and plays a role in strengthening. Meanwhile, Re hinders the growth of γ' at high temperature under stress. It is understood that the addition of Re is very important for improving the alloy properties, particularly the high-temperature properties, and therefore, the amount of Re added is controlled to 5.5 to 7%.

W, Mo elements are solid solution strengthening elements in the high-temperature alloy, and the atomic radius of W and Mo is larger, which can obviously cause lattice expansion in a matrix, thereby hindering the movement of dislocation and improving yield strength. The melting point of pure metal W can reach 3406 ℃, the melting point of the high-temperature alloy can be effectively improved, but the density of W reaches 19.3g/cm³The density of the alloy is greatly improved, the practical use of the alloy is not facilitated, and meanwhile, W is a TCP phase forming element, so that the mechanical property of the alloy under a high-temperature condition is reduced. Therefore, the content of W is controlled to be 4.5-6.5%. Excessive addition of Mo can cause reduction of hot corrosion performance of the alloy, and can accelerate peeling of a thermal barrier coating, excessive addition is not suitable, and the content of Mo is controlled to be 1-2.5%.

Al is one of the elements forming the gamma prime phase in the superalloy. The addition of Al can effectively improve the casting performance, the solid solution heat treatment capability, the phase stability, the mechanical property and the oxidation resistance of the alloy. The Al content affects the performance of the alloy, and the low content results in low gamma' volume fraction and insufficient strength; too high may result in an increased tendency to precipitate TCP phases, reducing the alloy structure stability. Therefore, the content of Al is controlled to be 5.55-5.95 percent;

ta is mainly distributed in the gamma 'phase, and the content of the gamma' phase is improved. Ta does not cause the formation of TCP phase, can improve the domain boundary energy of inversion and the gamma' dissolution temperature, and can effectively improve the high-temperature mechanical property of the alloy. Meanwhile, Ta can improve the casting performance, prevent the formation of freckles, improve the durable adhesive capacity of the aluminum plating coating and be beneficial to improving the casting performance of the alloy. Therefore, the amount of Ta added is controlled to 8% to 10%.

Nb is a gamma' phase strengthening element and can effectively improve the high-temperature strength of the alloy. But it is disadvantageous in corrosion resistance and oxidation resistance, so that the amount of Nb added is 0.4 to 0.6%.

Co is a solid solution strengthening element, inhibits the formation of Ni-Re bonds, promotes the uniform distribution of Re, and improves the structural stability of the alloy. Meanwhile, the addition of Co can reduce the stacking fault energy of the alloy and improve the creep resistance of the alloy. Therefore, the amount of Co added is controlled to 7% to 10%.

The addition of Cr can reduce the gamma' dissolving temperature, but the excessive content of Cr element can promote the precipitation of TCP and reduce the stability of the structure. Therefore, the amount of Cr added is controlled to be 2-4%.

Through a large number of early-stage process test researches, the grain boundary strengthening element C, B, Hf can strengthen the inevitable small-angle grain boundary of the single crystal high-temperature alloy, and meanwhile, trace rare earth elements La and Y are added into the alloy to improve the oxidation resistance and the corrosion resistance.

Preparation method of nickel-based single crystal alloy

The preparation method of the nickel-based single crystal alloy provided by the invention comprises the following steps: