CN102076877B - Ni-based single crystal superalloys and alloy components based on them - Google Patents

Abstract

The mass ratio of the components is as follows: al: 5.0 to 7.0 mass%, Ta: 4.0 to 8.0 mass% and Mo: 0 to 2.0 mass%, W: 3.0 to 8.0 mass%, Re: 3.0 to 8.0 mass%, Hf: 0 to 0.50 mass%, Cr: 3.0-6.0 mass%, Co: 0 to 9.9 mass%, Ru: 1.0 to 14.0 mass%, Nb: the present invention provides a Ni-based single crystal superalloy which comprises Ni in an amount of 0.1 to 4.0 mass% and the balance of Ni and unavoidable impurities, and which has high-temperature oxidation resistance while suppressing precipitation of a TCP phase at high temperature and improving strength at high temperature. That is, an object of the present invention is to provide a Ni-based single crystal superalloy having high performance that is well balanced between high-temperature strength and oxidation resistance at high temperatures in practical use. It is a further object of the present invention to provide a Ni-based single crystal superalloy having practically sufficient characteristics in a "heat treatment window" that cannot be neglected.

Description

Ni-based single crystal superalloys and alloy components based on them

technical field

The invention relates to a Ni-based single crystal superalloy with Al, Ta, W, Re, Cr, Ru and Nb as main additive elements and an alloy component based on it, especially to improving its high-temperature creep characteristics and high-temperature corrosion resistance Environmentally resistant technology.

Background technique

Among the typical compositions of Ni-based single crystal superalloys developed as materials for dynamic and stationary wings at high temperatures such as aircrafts and gas turbines, the compositions shown in Table 1 are listed, for example.

【Table 1】

In the above Ni-based single crystal superalloy, the Ni-based single crystal superalloy is obtained by performing a solution (Japanese: solution) treatment at a predetermined temperature and then performing an aging treatment. This alloy is called a so-called precipitation-solidified alloy, and has a form in which a γ' phase as a precipitate phase is precipitated in a γ phase as a parent phase.

Among the alloys listed in Table 1, CMSX-2 (manufactured by CannonMuskegon, see Patent Document 1) is called the first generation alloy, and CMSX-4 (manufactured by CannonMuskegon, see Patent Document 2) is called the second generation Alloys, Rene'N6 (manufactured by General Electric, see Patent Document 3), CMSX-10K (manufactured by CannonMuskegon, see Patent Document 4) are called third-generation alloys, 3B and MX-4 (manufactured by General Electric, see Patent Document 4) 5) It is called the fourth generation alloy.

The above-mentioned CMSX-2 as the first-generation alloy and CMSX-4 as the second-generation alloy have good creep strength at low temperatures, but after the solution treatment at high temperature, a large amount of eutectic γ' phase remains, which is consistent with Compared with the third generation alloys, the creep strength at high temperature is poor.

In addition, the aforementioned third-generation Rene'N6 and CMSX-10K are alloys aimed at improving creep strength at high temperatures compared to the second-generation alloys. However, since the composition ratio of Re (5% by mass or more) exceeds the amount of Re solid solution in the parent phase (γ phase), there is a problem that the remaining Re combines with other elements to precipitate a so-called TCP phase (Topologically Close Packed phase) at high temperature. ), and due to long-term use at high temperatures, the amount of the TCP phase increases and the creep strength decreases.

In addition, in order to improve the creep strength of Ni-based single crystal superalloys, an effective method is to make the lattice constant of the precipitated phase (γ' phase) slightly smaller than that of the parent phase (γ phase), but due to the Since the lattice constant fluctuates greatly depending on the composition ratio of the constituent elements of the alloy, it is difficult to finely adjust the lattice constant, and there is a problem that it is difficult to improve the creep strength. The inventors of the present invention have proposed a Ni-based single crystal superalloy which significantly prevents the precipitation of the TCP phase at high temperature and can improve the strength in view of the above-mentioned actual situation (Patent Documents 6 and 7).

Generally, when the above-mentioned high-temperature and high-strength Ni-based single crystal superalloy is used as a material for dynamic and static wings at high temperatures such as aircraft and gas turbines, the alloy is exposed to high-temperature combustion gases containing oxygen for a long time, so Improving the above-mentioned strength at high temperature and oxidation resistance and corrosion resistance at high temperature are important performance factors of the Ni-based single crystal superalloy that cannot be ignored. The above-mentioned Patent Documents do not show specific examples regarding oxidation resistance, but only describe qualitatively that Cr, Hf, Ta, etc. are effective for oxidation resistance. However, it is also described that Ru, which exhibits a remarkable effect on improving strength at high temperatures, degrades oxidation resistance and corrosion resistance at high temperatures (Patent Document 8). Fig. 1 is a graph showing the creep rupture life at 1100°C and 137 MP and the oxidation resistance at 1100°C of various representative existing alloys. Rene'N5 and CMSX-4 exhibit very excellent oxidation resistance properties. The above-mentioned existing alloys have improved oxidation resistance due to their high Cr content, but their life at high temperatures is not sufficient. On the other hand, the MX-4 alloy is known as a fourth-generation alloy very excellent in high-temperature heat resistance, but lacks oxidation resistance at high temperature. General Electric Corporation proposes a coating system including a diffusion barrier coating (diffusion barrier coating) for improving the oxidation resistance of MX-4 (Patent Document 6). As shown in the above-mentioned examples, it is difficult to develop Ni-based single crystal superalloys that have both life and strength at high temperatures and oxidation resistance, and this will become an important technical problem for the practical use of heat-resistant alloys in the future.

Patent Document 1: Specification of US Patent No. 4582548

Patent Document 2: Specification of US Patent No. 4,643,782

Patent Document 3: Specification of US Patent No. 5455120

Patent Document 4: Specification of US Patent No. 5366695

Patent Document 5: Specification of US Patent No. 5151249

Patent Document 6: Specification of US Patent No. 6966956

Patent Document 7: Specification of European Patent No. 1262569

Patent Document 8: Specification of US Patent No. 6,921,586

Contents of the invention

That is, an object of the present invention is to provide a high-performance Ni-based single crystal superalloy that achieves a practical balance between high-temperature strength and high-temperature oxidation resistance. Another object of the present invention is to provide a Ni-based single crystal superalloy that is practically characterized by having sufficient properties even in a "heat treatment window" that cannot be ignored.

In order to achieve the object, the present invention employs the following structures.

Invention 1 is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to 8.0% by mass, Mo: 0% by mass to 2.0% by mass Below, W: 3.0 mass % to 8.0 mass %, Re: 3.0 mass % to 8.0 mass %, Hf: 0 mass % to 0.50 mass %, Cr: 3.0 mass % to 7.0 mass %, Co: 0 mass % % to 9.9% by mass, Ru: 1.0 to 14.0% by mass, Nb: 0.1 to 4.0% by mass, and the remainder consists of Ni and unavoidable impurities.

Invention 2 is characterized in that it has the following composition, that is, it contains components in mass ratios as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to 10.0% by mass, Mo: 0% by mass but less than 1.1% by mass, W: 3.0% by mass to 6.0% by mass, Re: 3.0% by mass to 8.0% by mass, Hf: 0% by mass to 0.50% by mass, Cr: 3.0% by mass to 7.0% by mass, Co: 0% to 9.9% by mass, Ru: 1.0% to 8.0% by mass, Nb: 0.1% to 4.0% by mass, and the remainder is composed of Ni and unavoidable impurities.

Invention 3 is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to 8.0% by mass, Mo: 0% by mass to less than 1.1% by mass %, W: 3.0 mass % or more but less than 6.0 mass %, Re: 3.0 mass % or more and 8.0 mass % or less, Hf: 0 mass % or more but less than 0.12 mass %, Cr: 3.0 mass % or more and 7.0 mass % or less, Co: 0% to 9.9% by mass, Ru: 1.0% to 8.0% by mass, Nb: 0.1% to 4.0% by mass, and the remainder is composed of Ni and unavoidable impurities.

Invention 4 is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to 8.0% by mass, Mo: 0% by mass to less than 1.1% by mass %, W: 3.0 mass % or more but less than 6.0 mass %, Re: 5.8 mass % or more and 8.0 mass % or less, Hf: 0 mass % or more but less than 0.12 mass %, Cr: 3.0 mass % or more and 7.0 mass % or less, Co: 0% to 9.9% by mass, Ru: 1.0% to 8.0% by mass, Nb: 0.1% to 4.0% by mass, and the balance is composed of Ni and unavoidable impurities.

Invention 5 is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to 8.0% by mass, Mo: 0% by mass to less than 1.1% by mass %, W: 3.0 mass % or more but less than 6.0 mass %, Re: 5.8 mass % or more and 8.0 mass % or less, Hf: 0 mass % or more but less than 0.12 mass %, Cr: 3.0 mass % or more and 7.0 mass % or less, Co: 0% to 9.9% by mass, Ru: 4.1% to 8.0% by mass, Nb: 0.1% to 4.0% by mass, and the remainder consists of Ni and unavoidable impurities.

Invention 6 is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to less than 6.0% by mass, Mo: 0% by mass to less than 1.1% by mass Mass%, W: 3.0 mass% or more but less than 6.0 mass%, Re: 5.8 mass% or more and 8.0 mass% or less, Hf: 0 mass% or more but less than 0.12 mass%, Cr: 3.0 mass% or more and 7.0 mass% or less, Co : not less than 0% by mass and not more than 9.9% by mass, Ru: not less than 4.1% by mass and not more than 8.0% by mass, Nb: not less than 0.1% by mass and not more than 4.0% by mass, and the remainder consists of Ni and unavoidable impurities.

Invention 7 is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to less than 6.0% by mass, Mo: 0% by mass to less than 1.1% by mass Mass%, W: 3.0 mass% or more but less than 6.0 mass%, Re: 5.8 mass% or more and 8.0 mass% or less, Hf: 0.0 mass% or more but less than 0.12 mass%, Cr: 3.0 mass% or more and 7.0 mass% or less, Co : not less than 0% by mass and not more than 9.9% by mass, Ru: not less than 4.1% by mass and not more than 8.0% by mass, Nb: more than 1.0% by mass but not more than 3.0% by mass, and the remainder is composed of Ni and unavoidable impurities.

Invention 8 is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to less than 6.0% by mass, Mo: 0% by mass to less than 1.1% by mass % by mass, W: 4.0% by mass to less than 5.0% by mass, Re: 5.8% by mass to 8.0% by mass, Hf: 0.0% by mass to less than 0.12% by mass, Cr: 3.0% by mass to 7.0% by mass, Co : not less than 0% by mass and not more than 9.9% by mass, Ru: not less than 4.1% by mass and not more than 8.0% by mass, Nb: more than 1.0% by mass but not more than 3.0% by mass, and the remainder is composed of Ni and unavoidable impurities.

Invention 9 is characterized in that the Ni-based single crystal superalloy according to any one of Inventions 1 to 8 further contains Ti in a mass ratio of 2.0% by mass or less.

Invention 10 is characterized in that the Ni-based single crystal superalloy of any one of Inventions 1 to 9 contains at least one of B, C, Si, Y, La, Ce, V, and Zr.

Invention 11 is characterized in that, in the Ni-based single crystal superalloy according to any one of Inventions 1 to 10, when a1 is the lattice constant of the parent phase and a2 is the lattice constant of the precipitated phase, the difference between a1 and a2 is The relationship is 0.992a1≤a2<a1.

The alloy member based on a Ni-based single-crystal superalloy of Invention 12 is characterized in that the Ni-based single-crystal superalloy is the Ni-based single-crystal superalloy described in any one of Inventions 1 to 11.

Invention effect

By using the above-mentioned Ni-based single crystal superalloy system, by adding Ru, it is possible in principle to control the precipitation of the TCP phase at the time of high-temperature use, which causes a decrease in strength, and by setting the composition ratio of other constituent elements as described above. By setting the optimum range and controlling the lattice constant of the parent phase (γ phase) and the precipitated phase (γ' phase) to optimum values, an alloy excellent in high temperature strength can be obtained.

On the other hand, however, the fact that Ru degrades oxidation resistance at high temperature and corrosion resistance is known. The present invention not only optimizes the composition for the above-mentioned high-temperature strength improvement, but also aims at improving the oxidation resistance of the base material itself of the Ni-based single crystal superalloy, and found that the composition ratio of Ru and other constituent elements is further optimized. A practical Ni-based single crystal superalloy that has been adapted to achieve a balance between strength at high temperature and oxidation resistance.

That is, in the aforementioned Ni-based single crystal superalloy system, when the mass ratio of its components is as follows, namely, Al: 5.6 mass%, Ta: 5.6 mass%, Mo: 1.0 mass%, W: 4.8 mass% , Re: 6.4% by mass, Hf: 0.10% by mass, Cr: 4.6% by mass, Co: 5.6% by mass, Ru: 5.0% by mass, Nb: 1.1% by mass, and the remainder consists of Ni and unavoidable impurities. The creep rupture life at 1100° C. and 137 MPa is about 1,400 hours, and in the high-temperature oxidation accelerated test at 1100° C. with a cycle of 1.0 hour, the mass change can be minimized up to 50 cycles.

In addition, in the Ni-based single crystal superalloy system described above, Ti may be further contained in a mass ratio of 0 mass % or more and 2.0 mass % or less.

In addition, in the aforementioned Ni-based single crystal superalloy system, at least one of B, C, Si, Y, La, Ce, V, and Zr may be further contained.

In this case, it is preferable that the various components have mass ratios as follows: B: 0.05% by mass or less, C: 0.15% by mass or less, Si: 0.1% by mass or less, Y: 0.1% by mass or less, La: 0.1% by mass or less , Ce: 0.1 mass % or less, V: 1 mass % or less, Zr: 0.1 mass % or less.

Further, the Ni-based single crystal superalloy of the present invention is the aforementioned Ni-based single crystal superalloy, characterized in that when the lattice constant of the parent phase is a1 and the lattice constant of the precipitated phase is a2, 0.992 a1≤a2<a1.

Detailed ways

Embodiments of the present invention will be described in detail below.

The Ni-based single crystal superalloy of the present invention is an alloy in which Al, Ta, W, Re, Cr, Ru, and Nb are main additives, and Mo, Hf, and Co are used as adjustment additive elements.

The Ni-based single crystal superalloy of the present invention is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0 mass % to 7.0 mass %, Ta: 4.0 mass % to 8.0 mass %, Mo : 0 mass % to 2.0 mass %, W: 3.0 mass % to 8.0 mass %, Re: 3.0 mass % to 8.0 mass %, Hf: 0 mass % to 0.50 mass %, Cr: 3.0 mass % to 7.0 Mass % or less, Co: 0 mass % to 9.9 mass %, Ru: 1.0 mass % to 14.0 mass %, Nb: 0.1 mass % to 4.0 mass %, and the remainder consists of Ni and unavoidable impurities.

The Ni-based single crystal superalloy of the present invention is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0 mass % to 7.0 mass %, Ta: 4.0 mass % to 10.0 mass %, Mo : 0 mass % or more but less than 1.1 mass %, W: 3.0 mass % or more and 6.0 mass % or less, Re: 3.0 mass % or more and 8.0 mass % or less, Hf: 0 mass % or more and 0.50 mass % or less, Cr: 3.0 mass % or more 7.0 mass % or less, Co: 0 mass % to 9.9 mass %, Ru: 1.0 mass % to 8.0 mass %, Nb: 0.1 mass % to 4.0 mass %, and the remainder consists of Ni and unavoidable impurities.

The Ni-based single crystal superalloy of the present invention is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0 mass % to 7.0 mass %, Ta: 4.0 mass % to 8.0 mass %, Mo : 0% by mass to less than 1.1% by mass, W: 3.0% by mass to less than 6.0% by mass, Re: 3.0% by mass to 8.0% by mass, Hf: 0% by mass to less than 0.12% by mass, Cr: 3.0% by mass % to 7.0% by mass, Co: 0% to 9.9% by mass, Ru: 1.0% to 8.0% by mass, Nb: 0.1% to 4.0% by mass, and the remainder consists of Ni and unavoidable impurities constitute.

The Ni-based single crystal superalloy of the present invention is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0 mass % to 7.0 mass %, Ta: 4.0 mass % to 8.0 mass %, Mo : 0% by mass to less than 1.1% by mass, W: 3.0% by mass to less than 6.0% by mass, Re: 5.8% by mass to 8.0% by mass, Hf: 0% by mass to less than 0.12% by mass, Cr: 3.0% by mass % to 7.0% by mass, Co: 0% to 9.9% by mass, Ru: 1.0% to 8.0% by mass, Nb: 0.1% to 4.0% by mass, and the remainder consists of Ni and unavoidable impurities constitute.

The Ni-based single crystal superalloy of the present invention is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0 mass % to 7.0 mass %, Ta: 4.0 mass % to 8.0 mass %, Mo : 0% by mass to less than 1.1% by mass, W: 3.0% by mass to less than 6.0% by mass, Re: 5.8% by mass to 8.0% by mass, Hf: 0% by mass to less than 0.12% by mass, Cr: 3.0% by mass % to 7.0% by mass, Co: 0% to 9.9% by mass, Ru: 4.1% to 8.0% by mass, Nb: 0.1% to 4.0% by mass, and the remainder consists of Ni and unavoidable impurities constitute.

The Ni-based single crystal superalloy of the present invention is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to less than 6.0% by mass, Mo: 0% by mass to less than 1.1% by mass, W: 3.0% by mass to less than 6.0% by mass, Re: 5.8% by mass to 8.0% by mass, Hf: 0% by mass to less than 0.12% by mass, Cr: 3.0 Mass % to 7.0 mass %, Co: 0 mass % to 9.9 mass %, Ru: 4.1 mass % to 8.0 mass %, Nb: 0.1 mass % to 4.0 mass %, and the remainder consists of Ni and unavoidable Impurities constitute.

The Ni-based single crystal superalloy of the present invention is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to less than 6.0% by mass, Mo: 0% by mass to less than 1.1% by mass, W: 3.0% by mass to less than 6.0% by mass, Re: 5.8% by mass to less than 8.0% by mass, Hf: 0.0% by mass to less than 0.1% by mass, Cr: 3.0 Mass % to 7.0 mass %, Co: 0 mass % to 9.9 mass %, Ru: 4.1 mass % to 8.0 mass %, Nb: more than 1.0 mass % but 3.0 mass % or less, and the remainder consists of Ni and not Impurities to avoid constitute.

The Ni-based single crystal superalloy of the present invention is characterized by having the following composition, that is, the mass ratio of the components contained therein is as follows: Al: 5.0% by mass to 7.0% by mass, Ta: 4.0% by mass to less than 6.0% by mass, Mo: 0% by mass to less than 1.1% by mass, W: 4.0% by mass to less than 5.0% by mass, Re: 5.8% by mass to 8.0% by mass, Hf: 0.0% by mass to less than 0.1% by mass, Cr: 3.0 Mass % to 7.0 mass %, Co: 0 mass % to 9.9 mass %, Ru: 4.1 mass % to 8.0 mass %, Nb: more than 1.0 mass % but 3.0 mass % or less, and the remainder consists of Ni and not Impurities to avoid constitute.

Any of these alloys has a γ phase (parent phase) which is an austenite phase, and a γ′ phase (precipitated phase) which is a mesoregular phase dispersed and precipitated from the parent phase. The γ' phase is mainly composed of an intermetallic compound represented by Ni ₃ Al, and the high temperature strength of the Ni-based single crystal superalloy is improved by using the γ' phase.

Cr is an element excellent in oxidation resistance, and Ni improves the high-temperature corrosion resistance of the base single crystal superalloy.

The composition ratio of Cr is preferably Cr: 3.0% by mass to 7.0% by mass, more preferably 3.5% by mass to 6.5% by mass, most preferably 4.0% by mass to 6.0% by mass.

When the composition ratio of Cr is less than 3.0% by mass, it is not preferable because the desired high-temperature corrosion resistance cannot be ensured; when the composition ratio of Cr exceeds 7.0% by mass, since the precipitation of the γ′ phase is suppressed and the σ phase, μ It is also recognized that there is a tendency for the high-temperature strength to decrease, so it is not preferable.

Mo, in the coexistence of W and Ta, solid-solutes into the γ-phase as the parent phase to enhance high-temperature strength, and contributes to high-temperature strength by precipitation solidification. In addition, Mo greatly contributes to lattice mismatch and dislocation network spacing (described later) that are characteristic of this alloy.

The composition ratio of Mo is preferably in the range of 0.0% by mass to 2.0% by mass, more preferably in the range of 0.0% by mass to less than 1.1% by mass.

When the composition ratio of Mo exceeds 2.0% by mass, it is not preferable because desired oxidation resistance characteristics at high temperatures cannot be ensured in the composition domain of the Ni-based single crystal superalloy exemplified above.

In the coexistence of Ta and Mo as described above, W improves the high-temperature strength through the action of solid-solution strengthening and precipitation solidification.

When the composition ratio of W is less than 3.0% by mass, it is not preferable because the desired high-temperature strength cannot be ensured; when the composition ratio of W is too large, the high-temperature corrosion resistance is reduced, so it is not preferable. The composition ratio of W is preferably in the range of 3.0% by mass to 8.0% by mass, more preferably in the range of 3.0% by mass to 6.0% by mass, and most preferably in the range of 4.0% by mass to 5.0% by mass.

In the coexistence of W and Mo as described above, Ta increases the high-temperature strength through the action of solid solution strengthening and precipitation solidification, and partly precipitates and solidifies with respect to the γ' phase to improve the high-temperature strength.

The composition ratio of Ta is preferably in the range of not less than 4.0% by mass and not more than 8.0% by mass. When the composition ratio of Ta is less than 4.0% by mass, it is not preferable because the desired high-temperature strength cannot be ensured; when the composition ratio of Ta exceeds 10.0% by mass, the high-temperature strength is reduced due to the formation of σ phase and μ phase, so it is not preferable; In addition, from a practical point of view, when the composition ratio of Ta is 8.0% by mass or more, the density of the Ni-based single crystal superalloy also increases, which is not preferable. The most preferable composition ratio of Ta is in the range of 4.0% by mass or more and less than 6.0% by mass.

Al combines with Ni to form an intermetallic compound consisting of a γ' phase (Ni ₃ Al) finely and uniformly dispersed and precipitated in the parent phase at a ratio of 60 to 70% by volume, thereby improving high-temperature strength.

The composition ratio of Al is preferably in the range of 5.0% by mass or more and 7.0% by mass or less. When the composition ratio of Al is less than 5.0% by mass, it is not preferable because the amount of precipitation of the γ' phase is not sufficient and the desired high-temperature strength cannot be ensured; when the composition ratio of Al exceeds 7.0% by mass, it is called as The coarse γ' phase of the eutectic γ' phase is not preferable because solution treatment cannot be performed and high high temperature strength cannot be ensured.

Hf is an oxidation resistance improving element.

The composition ratio of Hf is preferably in the range of 0.00% by mass to 0.50% by mass, most preferably 0.01% by mass to less than 0.12% by mass. When the composition ratio of Hf is less than 0.01% by mass, it is not preferable because the effect of improving the oxidation resistance cannot be ensured. However, depending on the content of Al and/or Cr, the composition ratio of Hf may be 0% by mass or more but less than 0.01% by mass. In addition, when the composition ratio of Hf is too large, it is not preferable because local melting may occur and the high-temperature strength may decrease.

Co increases the solid solution limit at high temperature with respect to parent phases such as Al and Ta, and disperses and precipitates fine γ' phases by heat treatment, thereby improving high-temperature strength.

The composition ratio of Co is preferably in the range of 0.0% by mass to 9.9% by mass, more preferably in the range of 0.1% by mass to 9.9% by mass. When the composition ratio of Co is less than 0.1% by mass, it is not preferable because the precipitation amount of the γ' phase is insufficient and the desired high-temperature strength may not be ensured. However, depending on the content of Al and/or Ta, the composition ratio of Co may be less than 0% by mass or 0.1% by mass. In addition, when the composition ratio of Co exceeds 9.9% by mass, the balance with other elements such as Al, Ta, Mo, W, Hf, Cr is disrupted, harmful phases are precipitated, and the high temperature strength is lowered, so it is not preferable.

Re dissolves in the γ-phase which is the parent phase, and improves the high-temperature strength by solid-solution strengthening. In addition, there is also an effect of improving corrosion resistance. In addition, when a large amount of Re is added, the TCP phase, which is a harmful phase at high temperature, may precipitate and the high temperature strength may decrease.

The composition ratio of Re is preferably in the range of 3.0% by mass to 8.0% by mass, more preferably 5.8% by mass to 8.0% by mass.

When the composition ratio of Re is less than 3.0% by mass, it is not preferable because solid solution strengthening of the γ phase is insufficient and desired high-temperature strength cannot be ensured. When the composition ratio of Re exceeds 8.0% by mass, the TCP phase is precipitated at high temperature and the high-temperature strength performance is reduced. Also, if the amount of expensive Re is increased, the price of the alloy raw material increases, which is not preferable.

Ru suppresses the precipitation of the TCP phase, thereby improving the high-temperature strength.

The composition ratio of Ru is preferably in the range of 1.0% by mass to 14.0% by mass, more preferably in the range of 1.0% by mass to 8.0% by mass. The composition ratio of Ru is particularly preferably in the range of not less than 4.1% by mass and not more than 8.0% by mass.

When the composition ratio of Ru is less than 1.0% by mass, the TCP phase is precipitated at high temperature, and high high temperature strength cannot be ensured. Furthermore, when the composition ratio of Ru is less than 4.1% by mass, the high-temperature strength becomes lower than when the composition ratio of Ru is 4.1% by mass or more. When the composition ratio of Ru exceeds 8.0% by mass, it is not preferable because the high-temperature strength decreases due to the precipitation of the ε phase. In addition, increasing the amount of expensive Ru increases the price of alloy raw materials, so it is not preferable from the viewpoint of practicality.

The composition ratio of Nb is preferably in the range of 0.1 mass % to 4.0 mass %, more preferably more than 1.0 mass % but 3.0 mass % or less. Nb is a preferable element in terms of reducing the density of the Ni-based single crystal superalloy, but when the composition ratio of Nb is 3.0% by mass or more, it is not preferable because harmful phases are likely to be formed at high temperatures.

In the present invention, by adjusting the composition ratio of Al, Ta, Mo, W, Hf, Cr, Co, Re, Nb and Ni to the optimum composition ratio, the lattice constant of the γ phase and the Lattice mismatch and dislocation network spacing (described later) calculated from lattice constants are set in optimum ranges to improve high-temperature strength, and addition of Ru can suppress precipitation of TCP phase. In addition, especially by setting the composition ratio of Al, Cr, Ta, and Mo within the above-mentioned composition range, the production cost of the alloy can be suppressed. Furthermore, it is possible to improve specific strength and set lattice mismatch and dislocation network spacing to optimum values.

In addition, in a high-temperature use environment from 1273K (1000°C) to 1373K (1100°C), the lattice constant of the crystals constituting the γ-phase as the parent phase is a1, and the crystals constituting the γ'-phase as the precipitated phase When the lattice constant of the crystal is a2, the relationship between a1 and a2 is preferably a2<a1.

In the following description, the difference between the lattice constant a1 of the crystal of the parent phase and the lattice constant a2 of the crystal of the precipitated phase relative to a1 is {(a2-a1)/a1×100(%)} called "lattice mismatch".

With regard to the range of this lattice mismatch, within the range where the compatibility (compatibility) of the γ phase as the parent phase and the γ' phase as the precipitated phase can be maintained, by making it a further negative value, a reduced bit can be obtained. The effect of staggering the network spacing and improving the creep strength.

The lattice mismatch is less than 0%, preferably -0.1% or less, more preferably -0.15% or less.

However, when the value of the lattice mismatch is too negative, the matching cannot be maintained and the performance decreases, so it is at most -1%, preferably -0.8%, and more preferably -0.7%.

That is, the relationship between the lattice constant a2 of the crystal of the precipitated phase and the lattice constant a1 of the crystal of the parent phase is 0.990a1≤a2<a1, preferably 0.992a1≤a2≤0.999a1, more preferably 0.993a1≤a2≤0.9985 a1.

In the case where the lattice constants of the two have such a relationship, when the precipitated phase is precipitated in the parent phase by heat treatment, since the precipitated phase is precipitated in such a manner as to continuously extend in the direction perpendicular to the load direction, dislocation defects under stress The movement in the alloy structure is reduced, thereby increasing the creep strength. In order to control the relationship between the lattice constant a1 and the lattice constant a2 as described above, it is necessary to appropriately adjust the composition of the constituent elements constituting the Ni-based single crystal superalloy.

In addition, the Ni-based single crystal superalloy may further contain Ti. In this case, the composition ratio of Ti is preferably in the range of 0% by mass to 2.0% by mass. When the composition ratio of Ti exceeds 2.0% by mass, it is not preferable because harmful phases are precipitated and the high-temperature strength is lowered.

Alternatively, the high-temperature strength can also be improved by making the composition ratio of Ta, Nb, and Ti the total of both (Ta+Nb+Ti) 4.0% by mass or more and 10.0% by mass or less.

In addition, the Ni-based single crystal superalloy may contain, for example, B, C, Si, Y, La, Ce, V, Zr, etc. in addition to unavoidable impurities. In the case of containing at least one of B, C, Si, Y, La, Ce, V, and Zr, the composition ratio of each component is preferably as follows: B: 0.05% by mass or less, C: 0.15% by mass or less, Si: 0.1 mass % or less, Y: 0.1 mass % or less, La: 0.1 mass % or less, Ce: 0.1 mass % or less, V: 1 mass % or less, Zr: 0.1 mass % or less. When the composition ratio of each of the above-mentioned components exceeds the above-mentioned range, it is not preferable because harmful phases are precipitated to lower the high-temperature strength.

It should be noted that although there are alloys that cause reverse partitioning in conventional Ni-based single crystal superalloys, the Ni-based single crystal superalloy of the present invention does not cause reverse partitioning.

The creep rupture life and oxidation resistance of the Ni-based single crystal superalloy of the present invention described above are shown in FIG. 1 together with the characteristics of various representative existing alloys. Compared with Rene'N5, CMSX-4 and MX-4 alloys, the Ni-based single crystal superalloy of the present invention has extremely excellent characteristics in terms of life at high temperature and oxidation resistance.

In addition, the oxidation resistance degree of the vertical axis|shaft of FIG. 1 is defined by the following equation. Generally, when a sample of a Ni-based single crystal superalloy is oxidized at a high temperature, its mass may temporarily increase and then decrease due to oxidation, or may immediately decrease in mass after oxidation starts. This equation can express oxidation resistance in any case.

W1: mass increase after one cycle mg/cm ² )

W ₅₀ -W ₁ : Mass change from one cycle to 50 cycles (mg/cm ² )

(Example)

Next, examples are shown to explain the effects of the present invention.

The melts of various Ni-based single crystal superalloys are adjusted using a vacuum melting furnace, and a plurality of alloy ingots having different compositions are cast using the alloy melts. Alloy of the present invention (embodiment 1-3) together with 6 kinds of representative existing heat-resistant alloys (reference examples 1-6) and 4 kinds of the 4th and the 5th generation heat-resistant alloys that the applicant has applied for a patent ( The composition ratios of Reference Examples 7-10) (Patent Documents 6 and 7) are shown in Table 2.

【Table 2】

Next, solution treatment and aging treatment were performed on the alloy ingot, and the state of the alloy structure was observed with a scanning electron microscope (SEM). For the solution treatment of the alloys of Examples 1-3 and Reference Examples 7-10, after holding at 1573K (1300°C) for 1 hour, the temperature was raised to 1603K (1330°C) and held for 5 hours. In addition, the aging treatment was performed successively by performing one aging treatment at 1273K to 1423K (1000°C to 1150°C) for 4 hours, and two aging treatments at 1143K (870°C) for 20 hours. Regarding the conventional alloys of Reference Examples 1-6, solution treatment and aging treatment were performed on each alloy under known conditions. As a result, no TCP phase was confirmed in the structure of each sample.

2 is a transmission electron microscope photograph of a Ni-based single crystal alloy after solution treatment at 1335° C. for 18 hours and then aging treatment at 1150° C. for the alloy of Example 1. FIG. Dislocations formed in a network shape were observed, and the distance between the network cells was found to be about 0.32 mμ, making it suitable as a Ni-based single crystal alloy.

Next, a creep test was performed on each sample subjected to solution treatment and aging treatment. In the creep test, the hours before creep rupture of each sample (Examples 1 to 3 and Reference Examples 1 to 11) under the conditions of temperature and stress shown in Table 3 were measured as the lifetime. The results are summarized in Table 3.

Furthermore, the oxidation resistance test was performed on each sample subjected to the solution treatment and the aging treatment. The test conditions for oxidation resistance are: exposure to the sample in air at a high temperature of 1150° C. for a period of 1 hour to measure the mass change. Table 3 shows the oxidation resistance after 50 cycles.

【table 3】

Fig. 1 is about the creep rupture life under 1100 ℃, 137MP and the oxidation resistance under 1150 ℃, it is to the heat-resistant alloy of the present invention (embodiment 1-3), representative various existing practical alloy (reference example 1-6) and heat-resistant alloys (Reference Examples 7-10) (Patent Documents 6 and 7) that the inventors of the present application have applied for patents were compared. Typical existing practical alloys are insufficient in heat resistance. In addition, although the alloys proposed by the inventors of the present application have obvious advantages in heat resistance compared with practical alloys, in terms of oxidation resistance It cannot be considered to be sufficient. In addition, although the oxidation degree of the conventional alloy MX-4 of Reference Example 3 is not shown in the figure, the oxidation degree is 0.01 or less, which is significantly lower than other alloy systems. The results shown in Fig. 1 show that the alloy system of the present invention has both extremely excellent heat resistance and oxidation resistance compared with the above-mentioned conventional alloys.

FIG. 3 shows a comparison of the mass of the alloy of Example 1 and the alloy of Reference Example 4 when repeated exposure tests were performed at a high temperature of 1100° C. for about 600 cycles in the air at a cycle of 1 hour. Condition. This result shows that the alloy of the present invention has outstanding oxidation resistance compared with the conventional alloy CMSX-4 which is generally known to be excellent in oxidation resistance.

FIG. 4 is a view of the surface of the alloy of Example 1 after being exposed to air at 1100° C. for 1 hour. The surface of the alloy has a dense and thin multilayer structure including multiple alumina layers, which exhibits a characteristic of excellent oxidation resistance.

For Example 1 and CMSX-4 (Reference Example 4), which is a representative conventional alloy, the lattice mismatch values (%) were calculated, and they were -0.28 and -0.14, respectively. The alloy of Example 1 is preferably maintained as Compatibility between the γ phase of the parent phase and the γ' phase as the precipitated phase.

FIG. 5 is a graph showing heat-treatment windows measured for the alloy of Example 1 and the alloy of Reference Example 4, which is a practical alloy. The heat treatment windows of the alloys of Example 1 and Reference Example 4 are 47°C and 28°C, respectively. The heat treatment window of the alloy of the present invention has a larger window (window) than Reference Example 4 which is a practical alloy, and there will be no technical problems even in the industrial blade casting process. The yield of blades is very high.

Description of drawings

Fig. 1 is about the creep rupture life under 1100 ℃, 137MP and the oxidation resistance under 1150 ℃, is to the heat-resistant alloy (embodiment 1-3) of the present invention, representative existing practical alloy (reference example 1- 6) and a graph comparing the properties of the patented alloys (Reference Examples 7-10) of the inventors of the present application.

2 is a transmission electron microscope photograph of a Ni-based single crystal alloy after solution treatment and aging treatment of the alloy of Example 1. FIG.

Fig. 3 is a graph showing the time when the alloy of Example 1 and the alloy of Reference Example 4 of the practical alloy are repeatedly exposed to the sample at a high temperature of 1100°C for about 600 cycles in the air at a cycle of 1 hour. Quality change graph.

FIG. 4 is a photograph of the surface of the alloy of Example 1 after being exposed to air at 1100° C. for 1 hour.

Fig. 5 is a thermal analysis result after measuring a heat-treatment window (heat-treatment window) for the alloy of Example 1 and the alloy of Reference Example 4 which is a practical alloy.

Claims (11)

1. a Ni based single crystal superalloy, it is characterized in that, it is with Al, Ta, W, Re, Cr, Ru and Nb is main adding elements, by quality ratio, contain: more than Al:5.0 quality % 7.0 quality below %, more than Ta:4.0 quality % but be less than 6.0 quality %, more than Mo:0 quality % 1.0 quality below %, more than W:4.0 quality % but be less than 5.0 quality %, more than Re:5.8 quality % 8.0 quality below %, more than Hf:0.01 quality % and be less than below 0.12 quality %, more than Cr:3.0 quality % 7.0 quality below %, more than Co:0 quality % 9.9 quality below %, more than Ru:4.1 quality % 8.0 quality below %, more than Nb:0.1 quality % 4.0 quality below %, and remainder is made up of Ni and inevitable impurity.

2. a Ni based single crystal superalloy, it is characterized in that, it is with Al, Ta, W, Re, Cr, Ru and Nb is main adding elements, by quality ratio, contain: more than Al:5.0 quality % 7.0 quality below %, more than Ta:4.0 quality % but be less than 6.0 quality %, more than Mo:0 quality % 1.0 quality below %, more than W:4.0 quality % but be less than 5.0 quality %, more than Re:5.8 quality % 8.0 quality below %, more than Hf:0.01 quality % and be less than below 0.12 quality %, more than Cr:3.0 quality % 7.0 quality below %, more than Co:0 quality % 9.9 quality below %, more than Ru:4.1 quality % 8.0 quality below %, Nb: be greater than 1.0 quality % but be below 3.0 quality %, and remainder is made up of Ni and inevitable impurity.

3. a Ni based single crystal superalloy, it is characterized in that, it is with Al, Ta, W, Re, Cr, Ru and Nb is main adding elements, by quality ratio, contain: more than Al:5.5 quality % 5.6 quality below %, Ta:5.6 quality %, more than Mo:0.8 quality % 1.0 quality below %, more than W:4.8 quality % 5.2 quality below %, more than Re:6.4 quality % 6.5 quality below %, Hf:0.1 quality %, more than Cr:4.6 quality % 4.8 quality below %, more than Co:5.6 quality % 8.0 quality below %, Ru:5 quality %, Nb:1.2 quality %, and remainder is made up of Ni and inevitable impurity.

4. the Ni based single crystal superalloy as described in any one in claims 1 to 3, is characterized in that, further containing the Ti being below 2.0 quality % by quality ratio in this Ni based single crystal superalloy.

5. the Ni based single crystal superalloy as described in any one in claims 1 to 3, is characterized in that, containing at least one in B, C, Si, Y, La, Ce, V, Zr in this Ni based single crystal superalloy.

6. Ni based single crystal superalloy as claimed in claim 4, is characterized in that, containing at least one in B, C, Si, Y, La, Ce, V, Zr in this Ni based single crystal superalloy.

7. the Ni based single crystal superalloy as described in any one in claims 1 to 3, is characterized in that, when the lattice parameter of parent phase being set to a1, when the lattice parameter of precipitated phase is set to a2, the pass of a1 and a2 is 0.992a1≤a2 < a1.

8. Ni based single crystal superalloy as claimed in claim 4, is characterized in that, when the lattice parameter of parent phase being set to a1, when the lattice parameter of precipitated phase is set to a2, the pass of a1 and a2 is 0.992a1≤a2 < a1.

9. Ni based single crystal superalloy as claimed in claim 5, is characterized in that, when the lattice parameter of parent phase being set to a1, when the lattice parameter of precipitated phase is set to a2, the pass of a1 and a2 is 0.992a1≤a2 < a1.

10. Ni based single crystal superalloy as claimed in claim 6, is characterized in that, when the lattice parameter of parent phase being set to a1, when the lattice parameter of precipitated phase is set to a2, the pass of a1 and a2 is 0.992a1≤a2 < a1.

11. 1 kinds of alloy components that are base material with Ni based single crystal superalloy, it is characterized in that, described Ni based single crystal superalloy is the Ni based single crystal superalloy in claim 1 to 10 described in any one.