JP2005097650A - Ni-BASED SUPERALLOY - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new Ni-based superalloy having increased stability of the alloy structure to improve long-term reliability of a jet engine or a gas turbine without including Re and having creep strength equal to or higher than a conventional alloy. <P>SOLUTION: The high strength Ni-based superalloy has a stable structure and has composition containing: ≤20 wt.% of Cr; ≤10 wt.% of Mo; ≤15 wt.% of W; 2 to 10 wt.% of Al; ≤16 wt.% of Ta+Nb+Ti; ≤10 wt.% of Ru; and the balance Ni and inevitable impurities without including Re. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The invention of this application relates to a Ni-base superalloy, and more particularly, excellent in structural stability and creep characteristics at high temperatures, such as turbine blades such as jet engines and gas turbines, turbine vanes, turbine disks, and the like, The present invention relates to a new Ni-base superalloy suitable as a member used under high stress.

  Conventionally, as Ni-base superalloy, CMSX-10 (Co: 3.3wt%, Cr: 2.4wt%, Mo: 0.4wt%, W: 5.3wt%, Al: 5.7wt%, Ti: 0.2wt%, Nb : 0.1wt%, Ta: 8.2wt%, Hf: 0.03wt%, Re: 6.3wt% and the balance of Ni (Patent Document 1), TMS-138 (Co: 5.8wt%, Cr: 2.8wt) %, Mo: 2.9wt%, W: 6.1wt%, Al: 5.8wt%, Ta: 5.6wt%, Hf: 0.05wt%, Re: 5.1wt%, Ru: 1.9wt%, the balance being Ni ) (Patent Document 2) and the like are known as the most excellent in high temperature strength.

These conventional Ni-base superalloys are excellent in terms of creep strength up to 1100 ° C. as single crystal alloy members. However, since it contains a large amount of Re, it has a drawback that it tends to generate harmful crystals called TCP phase during long-time creep. In order to increase the long-term reliability of jet engines and gas turbines, it is important to increase the stability of the alloy structure. The realization of a Ni-base superalloy having an equivalent or higher creep strength has been desired.
US Pat. No. 5,366,695 European Patent Publication No. 12662569

  The invention of this application was made based on the background as described above, and does not contain Re, and is stable in structure as a high-temperature member such as a turbine blade or turbine vane of a jet engine or a gas turbine for a long time. The goal is to provide a new high-strength Ni-base superalloy.

  The invention of this application is to solve the above problems. First, Cr: 20 wt% or less, Mo: 10 wt% or less, W: 15 wt% or less, Al: 2-10 wt%, Ta + Nb Provided is a Ni-base superalloy characterized by containing + Ti: 16 wt% or less and Ru: 10 wt% or less, with the balance being composed of Ni and inevitable impurities.

  Second, there is provided a Ni-base superalloy characterized in that the alloy further contains Co: 20 wt% or less.

  Thirdly, in the alloys according to the first to second inventions, Hf: 10 wt% or less, Pt: 10 wt% or less, Rh: 10 wt% or less, V: 3 wt% or less, Zr: 3 wt% or less, Si There is provided a Ni-base superalloy characterized by containing any one element of: 3 wt% or less and Fe: 10 wt% or less.

  Fourth, Hf: 8 wt% or less, Pt: 10 wt% or less, Rh: 10 wt% or less, V: 2 wt% or less, Zr: 2 wt% or less, Si: 2 wt% or less, Fe: 10 wt% or less There is provided a Ni-base superalloy characterized by containing any two of the above.

  Fifth, Hf: 8 wt% or less, Pt: 10 wt% or less, Rh: 10 wt% or less, V: 2 wt% or less, Zr: 2 wt% or less, Si: 2 wt% or less, Fe: 10 wt% or less A Ni-base superalloy characterized by containing any three or more of the above is provided.

  In addition, the invention of this application is that, in any one of the above alloys, C: 0.3 wt% or less, B: 0.2 wt% or less, Y: 0.2 wt% or less, La: 0.2 wt% or less, Ce The present invention provides a Ni-base superalloy characterized by containing one or more elements of 0.2 wt% or less.

  Seventh, there is provided a turbine blade or turbine vane component characterized by being produced by a normal casting method, a unidirectional solidification method, or a single crystal solidification method using these alloys.

  Eighth, there is provided a turbine disk component produced by a powder metallurgy method or a forging method.

  According to the first invention of this application, it is possible to obtain a Ni-base superalloy that is stable in structure and excellent in creep strength over a long period of time.

  Further, the second invention has an effect of further improving the creep strength on the medium / low temperature side by containing Co.

  According to the third aspect of the invention, any one of the elements Hf, Pt, Rh, V, Zr, Si, and Fe is contained, and the creep strength at the low temperature side, oxidation resistance, structural stability, etc. It has the effect of further improving one characteristic.

  According to the fourth aspect of the invention, any two elements of Hf, Pt, Rh, V, Zr, Si, and Fe are contained, and the creep strength, oxidation resistance, structure stability, etc. on the medium / low temperature side It has the effect of further improving the two characteristics.

  According to the fifth aspect of the invention, any three or more elements of Hf, Pt, Rh, V, Zr, Si, and Fe are contained, and creep strength, oxidation resistance, and tissue stability on the medium / low temperature side are included. It has the effect of further improving three or more characteristics such as property.

  And according to the said 6th invention, by containing trace element of C, B, Y, La, and Ce individually or in combination, the effect of improving the strength of crystal grain boundaries and improving the oxidation resistance can be obtained. Demonstrate.

  In the seventh invention, by using a turbine blade and a turbine vane made of a new Ni-base superalloy for a jet engine or a gas turbine, they can be used for a long time, and reliability and the like are improved.

  In the eighth invention, by using a turbine disk made of a new Ni-base superalloy for a jet engine or a gas turbine, their long-term reliability is improved.

  The invention of this application has the features as described above, and an embodiment thereof will be described below.

  The invention of this application is characterized in that a high creep strength has been realized without adding Re, which has been considered essential for high-strength Ni-base superalloys, as will be described later in the examples. The composition will be described as follows.

  In the Ni-base superalloy of the invention of this application, Co is an effective element that improves the creep strength at medium and low temperatures. However, when the addition amount exceeds 20 wt%, harmful crystals called TCP phase are formed, and the creep strength is lowered. Moreover, it is preferable to set it as 0.1 wt% or more.

  Cr is necessary as an effective element for improving oxidation resistance and hot corrosion resistance. However, when the addition amount exceeds 20 wt%, harmful crystals called TCP phase are formed, and the creep strength is lowered. Moreover, it is preferable to set it as 0.1 wt% or more.

  Mo is necessary as an effective element that shifts the lattice constant misfit to a negative value to form a dense dislocation network at the interface between the gamma phase and the gamma 'phase, thereby improving the high-temperature creep strength. However, when the addition amount exceeds 10 wt%, harmful crystals called TCP phase are formed, and the creep strength is lowered. Moreover, it is preferable to set it as 0.1 wt% or more.

  Since W has the effect of improving the creep strength from high temperature to low temperature, it must be added to the alloy. However, if the addition amount exceeds 15 wt%, the formation of a harmful phase is promoted. Moreover, it is preferable to set it as 0.1 wt% or more.

  Al needs to be 2 wt% or more in order to form a gamma 'phase essential for improving the high temperature strength. However, if it exceeds 10 wt%, coarse crystals called eutectic gamma 'are formed and the creep strength is lowered. Therefore, it is necessary to set it as 2-10 wt%. More preferably, it is 4-8 wt%.

  Ta, Nb, and Ti are all effective elements that strengthen the gamma 'phase and improve the creep strength. Therefore, any one, two or three additions of these are required. In any case, when the sum is 16 wt% or more, the formation of harmful phases is promoted, so Ta + Nb + Ti needs to be 16 wt% or less. Moreover, it is preferable to set it as 0.1 wt% or more.

  Ru is an essential element for improving the creep strength on the low temperature side. However, if the added amount exceeds 10 wt%, the formation of a harmful phase is promoted, so it must be 10 wt% or less. The addition of Ru is preferably 0.1 wt% or more.

  Since Hf has the effect of improving oxidation resistance, it is effective to add it to the alloy. However, if the added amount exceeds 10 wt%, the formation of a harmful phase is promoted. Preferably it is 8 wt% or less.

  Pt has the effect of improving the structural stability and preventing the formation of harmful phases, so it is effective to add it to the alloy. However, if the added amount exceeds 10 wt%, the formation of a harmful phase is promoted.

  Since Rh also has the effect of improving the structural stability and preventing the formation of harmful phases, it is effective to add it to the alloy. However, if the added amount exceeds 10 wt%, the formation of a harmful phase is promoted.

  V has the effect of improving the creep strength on the low temperature side, so it is effective to add it to the alloy. However, if the added amount exceeds 3 wt%, the formation of a harmful phase is promoted. Preferably it is 2 wt% or less.

  Since Zr has the effect of improving the grain boundary strength, it is effective to add it to the alloy. However, if the added amount exceeds 3 wt%, the formation of a harmful phase is promoted. Preferably it is 2 wt% or less.

  Since Si has the effect of improving oxidation resistance, it is effective to add it to the alloy. However, if the added amount exceeds 3 wt%, the formation of a harmful phase is promoted. Preferably it is 2 wt% or less.

  Since Fe has the effect of improving the creep strength on the low temperature side, it is effective to add it to the alloy. However, if the added amount exceeds 10 wt%, the formation of a harmful phase is promoted.

  Since C has the effect of generating carbides at the grain boundaries and improving the creep strength, it is effective to add C to the alloy. However, if the added amount exceeds 0.3 wt%, the amount of carbide becomes excessive and the alloy becomes brittle, so it is necessary to make it less than this.

  Since B has the effect of segregating at the grain boundaries to improve the strength, it is effective to add B to the alloy. However, if the added amount exceeds 0.2 wt%, the melting point is lowered, so it is necessary to make it lower.

  Since Y has an effect of improving oxidation resistance, it is effective to add it. However, if the added amount exceeds 0.2 wt%, the oxidation resistance is lowered, so it is necessary to make it less than this.

  Since La has an effect of improving the oxidation resistance, it is effective to add La. However, if the added amount exceeds 0.2 wt%, the oxidation resistance is lowered, so it is necessary to make it less than this.

  Ce is effective to improve oxidation resistance, so it is effective to add it. However, if the added amount exceeds 0.2 wt%, the oxidation resistance is lowered, so it is necessary to make it less than this.

  The Ni-base superalloy of the present invention having the above compositional characteristics can be manufactured, for example, by casting as a single crystal and performing solution treatment and aging treatment. A unidirectionally solidified alloy may be used.

  For example, for solution treatment, in the range of 1200 ° C to 1350 ° C, for aging treatment, multi-stage treatment of primary aging at 1000 ° C or higher and secondary aging at 950 ° C or lower is considered suitable. Is done.

  Hereinafter, examples will be shown and described in more detail. Of course, the invention is not limited by the following examples.

  Ni-base superalloy (Example A composition: 5.7 wt% Cr, 1.0 wt% Mo, 12.5 wt% W, 4.7 wt% Al, 7.4 wt% Ta, 2.0 wt% Ru, remaining Ni, Example B composition: 7.9 wt % Co, 5.0wt% Cr, 2.8wt% Mo, 11.1wt% W, 4.9wt% Al, 7.8wt% Ta, 2.5wt% Ru, remaining Ni) are cast into a single crystal for solution treatment and aging treatment. went. In the solution treatment, after holding at 1270 ° C. for 1 hour, the temperature was raised to 1300 ° C. and held for 5 hours. As the aging treatment, a primary aging treatment was carried out at 1100 ° C. for 4 hours and a secondary aging treatment was carried out at 870 ° C. for 20 hours.

  Next, the creep strength was measured for the sample of this example that had undergone solution treatment and aging treatment. In the creep test, the time until the specimen ruptured at a temperature of 1100 ° C. and a stress of 137 MPa was defined as the lifetime.

  The creep test results of Example A and B alloys were compared with the prior art alloys, and the results are shown in FIG. FIG. 1 shows the 1% creep strain arrival time, which is an important value in equipment design. As is apparent from FIG. 1, the alloy of the present invention has a higher creep strength than the comparative example CMSX-10, which is called a third generation Ni-based single crystal alloy, and the fourth generation Ni-based single crystal alloy TMS-138. I understand.

  By the invention of this application, the structure stability and creep characteristics at high temperature are excellent, and it is suitable as a member used under high temperature and high stress such as turbine blades, turbine vanes, turbine disks, etc. of jet engines and gas turbines. Ni-base superalloy will be provided.

It is the figure which compared and showed the 1% creep strain arrival time of the alloy of the invention of this application, and the existing strongest alloy.

Claims (8)

  Contains Cr: 20 wt% or less, Mo: 10 wt% or less, W: 15 wt% or less, Al: 2-10 wt%, Ta + Nb + Ti: 16 wt% or less, Ru: 10 wt% or less, and the balance is inevitable with Ni A Ni-base superalloy having a composition comprising impurities.   The Ni-base superalloy according to claim 1, further comprising Co: 20 wt% or less.   The alloy according to claim 1 or 2, further comprising: Hf: 10 wt% or less, Pt: 10 wt% or less, Rh: 10 wt% or less, V: 3 wt% or less, Zr: 3 wt% or less, Si: 3 wt% or less, Fe: 10 wt% A Ni-base superalloy characterized by containing any one of the following elements:   3. The alloy according to claim 1, further comprising: Hf: 8 wt% or less, Pt: 10 wt% or less, Rh: 10 wt% or less, V: 2 wt% or less, Zr: 2 wt% or less, Si: 2 wt% or less, Fe: 10 wt% A Ni-base superalloy characterized by containing any two of the following elements.   3. The alloy according to claim 1, further comprising: Hf: 8 wt% or less, Pt: 10 wt% or less, Rh: 10 wt% or less, V: 2 wt% or less, Zr: 2 wt% or less, Si: 2 wt% or less, Fe: 10 wt% A Ni-base superalloy containing any three or more of the following elements:   6. The alloy according to claim 1, further comprising: C: 0.3 wt% or less, B: 0.2 wt% or less, Y: 0.2 wt% or less, La: 0.2 wt% or less, Ce: 0.2 wt% or less. A Ni-base superalloy containing one or more of the elements.   A turbine blade or turbine vane component produced by a normal casting method, a unidirectional solidification method, or a single crystal solidification method using the alloy according to any one of claims 1 to 6.   A turbine disk component produced by a powder metallurgy method or a forging method using the alloy according to any one of claims 1 to 6.

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