Nickel-base superalloy for producing parts by powder forming
阅读说明：本技术 通过粉末成型制造零件的镍基超合金 (Nickel-base superalloy for producing parts by powder forming ) 是由 S·J·理查德 J·拉姆 E·梅诺 于 2019-07-24 设计创作，主要内容包括：本发明涉及镍基超合金,按质量百分比,其含有：–5-6.5％铝；–4.5-7％钴；–14.5-16.5％铬；–0-0.2％铪；–0-1.5％钼；–2-3.5％钽；–0-2％钛；–1-2.5％钨；–0-0.08％锆；–0-0.03％硼；–0-0.07％碳；其余部分由镍和不可避免的杂质组成。(The invention relates to a nickel-based superalloy, which comprises the following components in percentage by mass: -5-6.5% aluminium; -4.5-7% cobalt; -14.5-16.5% chromium; -0-0.2% hafnium; -0-1.5% molybdenum; -2-3.5% tantalum; -0-2% titanium; -1-2.5% tungsten; -0-0.08% zirconium; -0-0.03% boron; -0-0.07% carbon; the remainder consisting of nickel and unavoidable impurities.)
1. A nickel-based superalloy, comprising, by mass percent:
-5-6.5% aluminium;
-4.5-7% cobalt;
-14.5-16.5% chromium;
-0-0.2% hafnium;
-0-1.5% molybdenum;
-2-3.5% tantalum;
-0-2% titanium;
-1-2.5% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
2. The superalloy of claim 1, wherein the superalloy comprises, in mass percent:
-5-6.5% aluminium;
-4.5-7% cobalt;
-14.5-16.5% chromium;
-0-0.2% hafnium;
-0-1.5% molybdenum;
-2-3.5% tantalum;
-0.5-2% titanium;
-1-2.5% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
3. The superalloy of claim 1, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
4. The superalloy as in claim 3, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0.5-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
5. The superalloy as in claim 4, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-1-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
6. The superalloy as in claim 3, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
7. The superalloy as in claim 3, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
8. The superalloy of claims 6 and 7, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
9. The superalloy of claims 4 and 7, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0.5-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
10. The superalloy of claims 4 and 6, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0.5-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
11. The superalloy of any of claims 6-10, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0.5-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
12. The superalloy of claim 11, wherein the superalloy comprises, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-1-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
13. A gas turbine part made from the nickel-base superalloy of any of claims 1 to 12.
14. A method of manufacturing a gas turbine component, the method comprising the steps of:
- (E1) manufacturing a nickel-base superalloy powder according to any of claims 1 to 12;
- (E2) producing the part by moulding the powder.
15. The method of claim 14, wherein the method comprises: a redissolution heat treatment step (E3) followed by a gamma prime precipitation heat treatment step (E4).
Background
The present invention relates to the general field of nickel-based superalloys for gas turbines, in particular blades (vanes), also known as nozzles or rectifiers, blades or ring segments.
Nickel-based superalloys are commonly used for high temperature components of gas turbines, i.e., gas turbine components located downstream of the combustor.
The main advantages of nickel-based superalloys are high creep resistance at high temperatures of 650 ℃ to 1200 ℃ and oxidation and corrosion resistance.
The high temperature resistance is mainly due to the microstructure of these materials, which consists of a matrix of gamma-Ni of face-centered cubic (FCC) crystal structure and an ordered hardened precipitate gamma' -Ni of L12 structure3And Al.
Nickel-base superalloy parts are typically manufactured by casting, the microstructure of the part being obtained by strictly controlling the casting process parameters and subsequently heat treating the part.
More recently, powder forming manufacturing processes have been used to manufacture nickel-base superalloy parts. As used herein, a powder forming process refers to a sintering (also referred to as a powder metallurgy process) or a manufacturing process by metal injection molding (MIM process) or by an additive manufacturing process (e.g., a binder jetting process or, for example, by a melt deposition process (or a melt filament fabrication (FFF) process)).
However, the mechanical properties of superalloy parts obtained by powder forming may be inferior to those of superalloy parts obtained by casting.
This reduction in the mechanical characteristics of the parts manufactured by powder forming is due to the fact that: the temperature range and heating and cooling rates used in the powder forming manufacturing process are very different from those used in the casting manufacturing process, and even if the two parts have the same composition, the parts manufactured by powder forming will not have the same microstructure as the parts manufactured by casting.
Is a known nickel-based superalloy commonly used in the casting of gas turbine components, particularly turbine blades.
For example, by a metal injection molding toolProduced by the process (MIM process)The part has a microstructure with a smaller grain size than the part made by casting, limiting the creep resistance of the part made by the MIM process.
In fact, this superalloy sintering during the MIM process is performed in the temperature range of titanium carbide precipitation (1200 ℃ to 1300 ℃), greatly limiting grain boundary movement and therefore the creation of coarse-grained microstructures by zener pinning after cooling.
Document WO 02/22901 is known, which describes a nickel-based superalloy.
Objects and summary of the invention
It is therefore an object of the present invention to provide a nickel-base superalloy composition suitable for manufacturing parts by shaping a nickel-base superalloy powder to improve the mechanical properties of the part, in particular the creep resistance.
In particular, it is an object of the present invention to maintain microstructural stability in the volume of the superalloy by ensuring low sensitivity to topologically compact phase TCP (chromium-, molybdenum-, and tungsten-rich μ or σ phase) formation.
It is also an object of the present invention to provide a superalloy having a gamma prime content similar to prior art superalloys used for casting.
It is also an object of the invention to provide an alloy whose density is not too high.
According to a first aspect, the present invention provides a nickel-base superalloy comprising, in mass percent:
-5-6.5% aluminium;
-4.5-7% cobalt;
-14.5-16.5% chromium;
-0-0.2% hafnium;
-0-1.5% molybdenum;
-2-3.5% tantalum;
-0-2% titanium;
-1-2.5% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
A nickel-based alloy is defined as an alloy based on the mass percent of nickel.
Unavoidable impurities are defined as those elements that are not intentionally added to the composition and brought along with other elements. Among the inevitable impurities, silicon (Si) may be particularly mentioned.
The superalloy according to the invention makes it possible to manufacture parts by powder forming, the microstructure of which is comparable to that of parts manufactured by casting with conventional alloys (suitable for casting).
The superalloy according to the present invention may in particular limit or even avoid the formation of carbides or other compounds during sintering, which tend to limit the movement of grain boundaries and thus the size of the grains.
According to a possible variant, the superalloy may contain, in mass percent:
-5-6.5% aluminium;
-4.5-7% cobalt;
-14.5-16.5% chromium;
-0-0.2% hafnium;
-0-1.5% molybdenum;
-2-3.5% tantalum;
-0.5-2% titanium;
-1-2.5% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
Further, the superalloy may contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
The superalloy may also contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0.5-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
According to a possible variant, the superalloy may also contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-1-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
The superalloy may further comprise, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
According to a possible variant, the superalloy may contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
According to another possible variant, the superalloy may contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
According to another possible variant, the superalloy may contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0.5-1.5% titanium;
-1.6-2% tungsten;
-0-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
According to another possible variant, the superalloy may contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0.5-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
According to a possible variant, the superalloy may contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-0.5-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
According to a possible variant, the superalloy may contain, in mass percent:
-5.6-6% aluminium;
-5.2-6.2% cobalt;
-15.4-16% chromium;
-0.1-0.15% hafnium;
-0.5-0.9% molybdenum;
-2.5-2.9% tantalum;
-1-1.5% titanium;
-1.6-2% tungsten;
-0.04-0.08% zirconium;
-0-0.03% boron;
-0-0.07% carbon;
the remainder consisting of nickel and unavoidable impurities.
According to a second aspect, the invention provides a gas turbine part made of a nickel-base superalloy according to any of the preceding features.
The part may be a turbine component of an aircraft gas turbine engine (e.g., a high pressure turbine or a low pressure turbine), or a compressor component, particularly a high pressure compressor component.
According to other features, the turbine or compressor part may be a blade, which can be a moving blade or vane, or an annular segment.
According to a third aspect, the invention provides a method for manufacturing a gas turbine part, the method comprising the steps of:
-manufacturing a nickel-base superalloy powder according to any of the above features;
-producing the part by powder forming.
The nickel-base superalloy powder forming process may be performed by sintering a nickel-base superalloy powder or by additive manufacturing from the powder, or by metal injection molding (MIM process) from the powder.
According to other features, the method includes: a redissolution heat treatment step followed by a gamma prime precipitation heat treatment step.
Drawings
Further features and advantages of the present invention will appear from the description provided hereinafter, with reference to the accompanying drawings, which show an exemplary embodiment without any limiting features.
Fig. 1 schematically shows the steps of a method of manufacturing a gas turbine part according to a possible variant of the invention.
Detailed Description
The superalloy according to the present invention comprises a nickel base associated with a primary additive element.
The main added elements include: cobalt Co, chromium Cr, molybdenum Mo, tungsten W, aluminum Al, and tantalum Ta. The primary additive element may also include titanium Ti.
The superalloy may also include minor additions that are up to a maximum percentage of 1 mass% in the alloy.
The secondary added elements include: hafnium Hf, carbon C, boron B and zirconium Zr.
The nickel-based superalloy comprises, by mass percent: 5% to 6.5% of aluminium, 4.5% to 7% of cobalt, 14.5% to 16.5% of chromium, 0% to 0.2% of hafnium, 0% to 1.5% of molybdenum, 2% to 3.5% of tantalum, 0% to 2% of titanium, 1% to 2.5% of tungsten, 0% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
The superalloy composition improves the high temperature mechanical resistance properties of the manufactured part by shaping a powder composed of the superalloy.
This improvement in mechanical properties is achieved by creating a microstructure in the powder formed superalloy component that tends to resemble the microstructure of prior art superalloy components made by casting.
The superalloy according to the present invention is suitable for temperatures used during powder forming manufacturing, which are lower than temperatures used in casting processes.
Tungsten, chromium and cobalt primarily participate in the hardening of the face-centered cubic (FCC) crystal structured austenitic matrix, also known as the gamma (gamma) matrix. The hardening is achieved by replacing the nickel with tungsten, chromium and cobalt.
In addition, preferably, the superalloy may comprise molybdenum, since molybdenum also participates mainly in the hardening of the γ -matrix by replacing nickel.
Aluminum and tantalum promote Ni of ordered cubic structure L123Precipitation of the hardening phase (Al, Ta), also known as the gamma (gamma') phase.
In addition, preferably, the superalloy may include titanium, as titanium also promotes Ni3Precipitation of hardening phases (Al, Ta, Ti) (γ' phase).
In addition, the refractory elements (i.e., molybdenum, tungsten, and tantalum) also slow the diffusion-controlled mechanism, thereby improving the creep and oxidation resistance of the superalloy.
In addition, chromium and aluminum improve the oxidation and corrosion resistance of the superalloy at high temperatures (particularly about 900 ℃ for corrosion and about 1100 ℃ for oxidation).
The addition of chromium and cobalt also lowers the gamma prime solution temperature of the superalloy.
In addition, cobalt enhances the gamma matrix and reduces susceptibility to topologically compact phase TCP precipitation and secondary reaction zone SRZ formation. However, cobalt often lowers the γ' solution temperature.
Advantageously, the superalloy may also contain hafnium, by adding Al2O3Improved resistance to thermal oxidation by adhesion of an alumina layer, said Al2O3An aluminum oxide layer is formed on the superalloy at high temperatures in an oxidizing environment.
In addition, the addition of carbon, boron and zirconium enhances the resistance of grain boundaries, thereby improving the corrosion resistance of parts made from superalloys.
Preferably, the nickel-base superalloy comprises, in mass percent: 5% to 6.5% of aluminium, 4.5% to 7% of cobalt, 14.5% to 16.5% of chromium, 0% to 0.2% of hafnium, 0% to 1.5% of molybdenum, 2% to 3.5% of tantalum, 0.5% to 2% of titanium, 1% to 2.5% of tungsten, 0% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
The titanium content of 0.5 to 2% by mass improves the creep resistance.
The nickel-based superalloy may further comprise, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 0% to 1.5% of titanium, 1.6% to 2% of tungsten, 0% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
Preferably, the superalloy comprises, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 0.5% to 1.5% of titanium, 1.6% to 2% of tungsten, 0% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
The titanium content of 0.5 to 1.5% by mass further improves the creep resistance.
More preferably, the superalloy comprises, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 1% to 1.5% of titanium, 1.6% to 2% of tungsten, 0% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
The 1 to 1.5% titanium content further improves creep strength by mass.
The superalloy may further comprise, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 0% to 1.5% of titanium, 1.6% to 2% of tungsten, 0.04% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
The corrosion resistance is improved by the zirconium content of 0.04 to 0.08% by mass and the boron content of 0.03% and 0.07% by mass.
The superalloy may further comprise, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0.1% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 0% to 1.5% of titanium, 1.6% to 2% of tungsten, 0% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
A hafnium content of 0.1% to 0.15% hafnium improves the mechanical properties of the superalloy.
Preferably, the superalloy comprises, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0.1% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 0% to 1.5% of titanium, 1.6% to 2% of tungsten, 0.04% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
The superalloy may further comprise, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0.1% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 0.5% to 1.5% of titanium, 1.6% to 2% of tungsten, 0% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
The superalloy may further comprise, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 0.5% to 1.5% of titanium, 1.6% to 2% of tungsten, 0.04% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
Preferably, the superalloy comprises, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0.1% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 0.5% to 1.5% of titanium, 1.6% to 2% of tungsten, 0.04% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
More preferably, the superalloy comprises, in mass percent: 5.6% to 6% of aluminium, 5.2% to 6.2% of cobalt, 15.4% to 16% of chromium, 0.1% to 0.15% of hafnium, 0.5% to 0.9% of molybdenum, 2.5% to 2.9% of tantalum, 1% to 1.5% of titanium, 1.6% to 2% of tungsten, 0.04% to 0.08% of zirconium, 0% to 0.03% of boron, 0% to 0.07% of carbon, the remainder consisting of nickel and unavoidable impurities.
Superalloys can produce gas turbine components with good mechanical resistance at high temperatures.
As shown in FIG. 1, a method of manufacturing a gas turbine component includes the steps of:
-E1: making a nickel-base superalloy powder as described above;
-E2: the parts are produced by powder molding.
In order to give the nickel superalloy powder the desired composition, step E1 of manufacturing the nickel superalloy powder is performed by atomizing a previously prepared melt. Atomization can be carried out with an inert gas such as molecular nitrogen, helium or argon.
Step E2 of manufacturing a part by shaping the powder obtained in step E1 may be performed by sintering (also known as powder metallurgy process) or additive manufacturing or by metal injection molding (MIM process).
The powder is provided with the shape of the part to be produced by filling a mold, and then the powder is compressed and heated to bond the powder particles by diffusion, thereby being manufactured by sintering the powder. The cohesion of the parts is obtained by the phenomenon of diffusion, without the powders fusing. The sintering temperature may be 1220 to 1320 ℃.
Additive manufacturing from superalloy powders may be performed by binder jetting. For this purpose, a thin layer of powder is deposited on the tray. Then, depending on the shape of the part to be manufactured, a binder is sprayed onto the powder layer to bind the different powder particles together, thereby producing a first basic part of the part. Once the first basic portion of the part is manufactured, the pallet is lowered and a new layer of powder is deposited on the first basic portion of the part to be manufactured. Also here, once the powder layer is applied, the binder is sprayed to form a second base portion of the part. These operations are then repeated to produce the entire part. The binder is then removed and the part is sintered, for example at a temperature of 1220 ℃ to 1320 ℃.
According to another possible variant, the additive manufacturing of the part may be performed by a melt deposition process (or a melt filament fabrication (FFF) process). To this end, a superalloy powder is mixed with a plastic binder and then shaped to form a filament. The filaments formed by mixing the metal and plastic binder are then melted in a controlled manner and the melt is deposited in a manner that shapes it into the part to be manufactured. Once the part has been formed by depositing material from the filaments, the plastic binder can be removed, for example by heating, to obtain a part consisting only of the superalloy. Once the plastic binder is removed, the part is sintered at a sintering temperature of from 1220 ℃ to 1320 ℃.
According to another possible variant, the additive manufacturing of the part may be performed by Selective Laser Melting (SLM). For this purpose, a thin layer of superalloy powder is deposited on the tray. The laser beam then selectively melts the powder to form a first substantial portion of the part, and the atmosphere is controlled so as not to contaminate the superalloy. Once the first base part is manufactured, the platen is lowered and a new layer of powder is deposited on the first base part of the part. This new layer of powder is then selectively melted by the laser to produce a second elementary portion of the part. These operations are then repeated to produce the entire part.
According to another possible variant, the additive manufacturing of the part is performed by Electron Beam Melting (EBM), a process similar to selective laser melting, in which the powder is melted by an electron beam instead of a laser, the powder being in vacuum.
Step E2 of manufacturing the part by powder molding may be performed by Metal Injection Molding (MIM). For this purpose, the superalloy powder is mixed with a plastic binder. The mixture is then injected to give the part its shape. Once formed, the binder is removed, for example by heating, to obtain a part consisting only of the nickel-base superalloy. Once the plastic binder is removed, the part is sintered, for example at a temperature of 1220 ℃ to 1320 ℃.
Further, as shown in fig. 1, the manufacturing method may include: a redissolution heat treatment step E3 followed by a gamma prime precipitation heat treatment step E4.
The redissolution heat treatment step E3 is carried out by heating the part at a temperature and for a time suitable to cause dissolution of the gamma prime precipitates formed during the manufacture of the part. The temperature of the redissolution heat treatment is below the solidus temperature to avoid local melting of the gamma matrix.
The redissolution heat treatment step E3 can be carried out by heating the part to a temperature of 1100 ℃ to 1300 ℃ (typically 1200 ℃) for a period of 1 hour to 5 hours (typically 3 hours).
In addition, the re-solution heat treatment step E3 enlarges the grains of the microstructure of the part.
The gamma prime precipitation heat treatment step E4 is carried out by one or more aging steps to re-precipitate the gamma prime phase in the desired form.
The E4 precipitation heat treatment step of the gamma' phase can be carried out, for example, by a first aging at a temperature of 800 ℃ to 900 ℃ (typically 850 ℃) followed by a second aging at a temperature of 700 ℃ to 800 ℃ (typically 750 ℃). The first aging resulted in precipitation of large gamma prime precipitates and the second aging resulted in precipitation of small gamma prime precipitates.
The manufactured part may have an equiaxed crystal structure, i.e. the grain size of the crystal structure is substantially equal in all directions. The equiaxed structure is achieved by sintering the powder, since sintering does not orient the grains.
However, the present invention is not limited to the fabrication of parts having equiaxed crystal structures. For example, parts with oriented grains can be manufactured using variants that manufacture parts by selective laser melting (SLM process) or electron beam melting (EBM process).
The superalloy according to the invention is suitable for manufacturing blades for gas turbines. The blades may be blades of a compressor, and preferably blades of a high pressure compressor operating at a higher temperature than a low pressure compressor, or the blades may be turbine blades.