CA1053482A - Nickel-base superalloy cast article - Google Patents
Nickel-base superalloy cast articleInfo
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- CA1053482A CA1053482A CA215,680A CA215680A CA1053482A CA 1053482 A CA1053482 A CA 1053482A CA 215680 A CA215680 A CA 215680A CA 1053482 A CA1053482 A CA 1053482A
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- nickel
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
- C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
- C22C19/057—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being less 10%
Abstract
ABSTRACT OF THE DISCLOSURE
A nickel-base superalloy cast article is provided with improved stress rupture and creep properties as a result of providing its microstructure with aligned cellular dendrites in combination with the substantial absence of NiAl, carbon, carbides, and Ti. The superalloy consists, in atomic percent, essentially of 4-11 Cr. 5-16 Al, at least 0.5 R?, up to about 10V, up to about 15 Co, up to about 5 Ta, up to about 5W, up to about 1 Mo, up to about 2.5 Mn, up to about 2.5 Rh, with the balance nickel and incidental impurities.
The alloy is suited for use in gas turbines.
A nickel-base superalloy cast article is provided with improved stress rupture and creep properties as a result of providing its microstructure with aligned cellular dendrites in combination with the substantial absence of NiAl, carbon, carbides, and Ti. The superalloy consists, in atomic percent, essentially of 4-11 Cr. 5-16 Al, at least 0.5 R?, up to about 10V, up to about 15 Co, up to about 5 Ta, up to about 5W, up to about 1 Mo, up to about 2.5 Mn, up to about 2.5 Rh, with the balance nickel and incidental impurities.
The alloy is suited for use in gas turbines.
Description
Background of the Invention This invention relates to nickel-base superalloys and to cast articles having an aligned cellular dendritic structure, for example as a re~3ult of unidirectional solidification.
More recent efforts in the development of nickel-base superalloys and their articles for use under strenuous operating conditions such as are found in gas turbine engines includes emphasis on composite eutectic alloys. Such alloys include reinforcing carbide members such as fibers which can be formed in situ during solidification of the alloy. One form of such solidification which ~as been used and has been widely reported iæ generally referred to as unidirectional solidification.
Creation of such carbide reinforced alloys obviously requires the addition of the element carbon. However, during the study of such alloys, it was recognized that detrimental interaction can occur at the interface between the carbide and the matrix. In addition, carbides can provide a source for crack initiation.
It has been recognized that the gamma prime former Ti, when included in a nickel-base superalloy structure, depresses the alloy's incipient melting temperature and tends to promote the formation of a eutectic phase for example, the gamma-gamma prime eutectic. With Ti, the incipient melting temperature is about 2250F.
Summary of the Invention It is a principal object of the present invention to provide an improved cast nickel-base superalloy article, the microstructure of which is substantially free of carbon, carbides, titanium and phases which are detrimental to high temperature strength properties.
lOS348Z 1 3DV-630 1 Another object is to provide a castable nickel-base superalloy sub6tantially free of carbon and titanium and which is particularly useful in the casting of unidirectionally solidified articles.
These and other objects and advantages will be more clearly understood from the following detailed description, the drawings and the examples all of which are intended to be typical of rather than in any way limiting on the scope of the present invention.
Briefly, the present invention, in one form, provides a cast nickel-base superalloy article the microstructure of which comprises aligned cellular dendrites and is further characterized by the substantial absence of the detrimental NiAl phase, carbon, carbides and Ti. The superalloy associated with the present invention consists, in atomic percent, essentially of 4-11 Cr, 5-16 Al, at least 0. 5 Re, up to about 10 V, up to about 15 Co, up to about 5 Ta, up to about 5 W, up to about 1 Mo, up to about 2. 5 Mn, up to about 2. 5 Rh, with the balance Ni and incidental impurities. Such incidental impurities may include Ti at less than 1 and C at less than 0.1 at. % which, by weight, is less than about 0. 017%. It is also preferred that the elements Zr and B be omitted from the composition, their presence being limited to those levels which result from normal pick-up of stray elements during melting and casting, for example up to about 0. 03% Zr and 0. 01% B by weight.
For comparison purposes, the approximate percent by weight equivalent of this form of the invention consists essentially of 3. 5-10 Cr; 2. 2-7. 2 Al; at least 1. 5 Re; up to about 8. 5 V; up to about 15 each of Co, Ta and W; up to about 1. 5 Mo; up to about 2. 5 Mn; up to about 4. 5 Rh; with the balance Ni and incidental impurities.
In a preferred form of the present invention, the composition, and atomic percent, consist essentially of 3-8 Co, 4-9 Cr, 8-14 Al, 1-4 Ta, 1053~8Z 1 3DV - 63 01 1-7 V, 0. 5-5 Re, up to about 2 W, up to about 1 each of Mo, Mn and Rh, with the balance essentially nickel and incidental impurities. For comparison purposes, the approximate percent by weight equivalent of this preferred form consists essentially of 3-8 Co; 3. 5-8 Cr; 3. 6-6. 3 A1; 3-12 Ta; 0. 8-6 V;1. 5-15 Re; up to about 6 W; up to about 1. 5 Mo; up to about 1 Mn; up to about 1. 8 Rh; with the balance Ni and incidental impurities.
Brief Description of the Drawings FIG. 1 is a photomicrographic view at 100 magnifications of the structure OI example 105 within the scope of the present invention showing the aligned cellular dendrites in the transverse directionand the absence of NiAl;
FIG. 2 is a photomicrographic view at 100 magnifications of the structure of example 105 within the scope of the present invention showing the aligned cellular dendrites in the longitudinal direction and the absence of 1 5 NiAl;
FIG. 3 is a photomicrographic view at 100 magnifications in the transverse direction of the alloy of example 87 outside the scope of the present invention showing the presence of abundant gamma-gamma prime eutectic phase;
FIG. 4 is a photomicrographic view at 100 magnifications in the transverse direction of the alloy of example 145 outside the scope of the present invention showing the presence of NiAl phase; and FIG. 5 is a graphical comparison of creep properties.
Description of the Preferred Embodiments In order to provide an improved nickel-base superalloy article useful under such strenuous operating conditions as are found in the turbine section of a modern gas turbine engine, and to remove the carbide 1053~8Z
strengthening mechanism from the alloy of such article, it is necessary to design such alloy with significantly larger amounts of other strengthening elements. The principal strengthening mechanism remaining after carbide elimination is the gamma prime phase, which is predominantly Ni3Al, in the gamma matrix, which is predominantly nickel. However, the gamma prime and the gamma phases can be strengthened with the addition of alloying elements. One of the problems which exists in the addition of significantly higher levels of alloying elements is that the detrimental NiAl phase can be forced to form, particularly at higher Al values. Further, the combination of elements can move the alloy into that portion of the alloy's phase diagram which causes the formation of gamma-gamma prime eutectic. The NiAl causes a significant and dramatic reduction in high temperature properties and the gamma-gamma prime eutectic lowers the incipient melting point of the alloy.
The present invention defines a unique castable nickel-base superalloy which is not strengthened by any carbide mechanism and which includes a balance of alloying elements providing strength characteristics even greater than the carbide strengthened type superalloy structures. At the same time, its structure is extremely uniform, includes substantially no NiAl phase and avoids the gamma-gamma prime eutectic. As a result, the incipient melting temperature of the alloy associated with the present irnvention is at least about 100F higher than an ordinary superalloy's incipient melting temperature of about 2250~F. In addition, through the inclusion of a balance of elements which strengthen the gamma prime precipitate phase, the gamma prime solution temperature is at least 100 higher than that of the ordinary superalloy. Furthermore, the alloy is uniquely adapt.od for unidirectional solidification to provide that structure l(~S348'~
defined as an aligned cellular dendritic structure. Thus, an article having such a structure and made from the composition provided by the present in~rention has a higher temperature operating capability as well as over-temperature protection in that the chances of causing incipient melting of the article are reduced.
The present invention will be more fully understood from the following discussion of representative examples of alloy forms studied during the evaluation of the present invention. Such examples are grouped for ready comparison but are not intended to be limitations on the invention's scope.
The alloy associated with the present invention, in atomic percent, consists essentially of 4-11 Cr, 5-16 Al, at least 0. 5 Re, up to about lOV, up to about 15 Co, up to about 5 each of Ta and W, up to about 1 Mo, up to about 2. 5 each of Mn and Rh, with the balance essentially nickel and incidental impurities. However, the preferred form of such alloy, in atomic percent, consists essentially of 3-8 Co, 4-9 Cr, 8-14 Al, 1-4 Ta, 1-7 V, 0. 5-5 and more preferably 0.5 - 3 Re, up to about 2 W, up to about 1 each of Mo, Mn and Rh, with the balance essentially Ni and incidental impurities. The following Table I lists the compositions of selected forms of such alloy within the preferred range of the present invention and Table II
lists some of each form's mechanical property data. None of the elements C, Ti, B or Zr, usually found in nickel-base superalloys, were added and are to be specifically avoided, except in impurity amounts, according to the present invention. Unless otherwise specified throughout this specification, all compositions are in atomic percent.
~05348Z 13DV-6301 TAB LE I -Preferred form of Invention Composition (Atomic ~o) Balance Ni Example Co Cr Al Ta V Re W Mo Mn Rh 105 3.5 5.4 12.7 2.25.5 2.0 106 3.5 5.4 12.8 1.45.5 2.0 0.9 118 3.5 5.4 12.7 2.25.5 1.5 0.5 122 3.5 5.4 12.7 2.25.5 1.0 1.0 123 3.5 5.4 12.7 2.25.5 0.5 1.5 124 3.5 5.4 12.7 2.75.5 1.5 125 3.5 5.4 12.7 3.25.5 1.0 127 3.5 5.4 12.7 2.25.5 1.5 0.5 128 3,5 5.4 12.7 2.25.5 1.0 1.0 133 3.5 5.4 12.7 2.25.5 1.5 0.5 134 3.5 5.4 12.7 2.25.5 1.0 1.0 136 3.5 5.9 12.7 2.25.5 1.5 146 3.5 7.0 12.2 2.15.3 2.0 147 3.5 8.5 11.7 2.15.0 2.0 l~S3~8Z 13~V-6301 TABLE II
Mechanical Properties of Preferred Form Stress Rupture _ Tensile (1200F) 1650F/60 ksi 1800~F/35 ksiUltimateYield R.A.
Example Life(hrs) R. A. Life(hrs) R. A.(ksi)(ksi) (%) As used in tables herein, the terms "ksi" means "thousands of pounds per square inch" and "RA" means "Reduction in Area". All of the data were obtained by testing in air under the conditions identified.
In order to provide cast stress rupture, tensile and creep specimens for each of the alloys evaluated in connection with the present invention, each alloy form was cast and unidirectionally solidified at the rate of about 20 inches per hour to create the aligned cellular dendritic structure which characterizes the article of the present invention. Such structure is aligned predominantly in the ~001> direction, which is equivalent to the<100>
and ~Ol(~directions. Photomicrographic studies of each of the alloys in Table I showed no NiAl phase present. Referring to the drawings, FIGS. 1 and 2 are photomicrographs at 100 magnifications of example 105, typical of the microstructure of the present invention. They show the aligned cellular dendritic structure which resulted from unidirectional solidification, FIG. 1 being in the transverse direction and FIG. 2 being in the longitudinal direction.
The elongated dendrites are more clearly shown in FIG. 2. The absence of the dark NiAl phase, shown in FIG. 4,to be discussed later, is particularly evident in FIGS. 1 and 2.
As was mentioned before, NiAl phase is dramatica~ly detrimental to stress rupture properties and hence one of the important characteristics of the present invention is that no NiAl is present in the alloy's microstructure. The data of Table II clearly shows the significantly improved stress rupture properties of the present invention at no sacrifice of tensile proper~ies even though no carbide strengthening is present and the gamma prime strengthener Ti has not been included as an alloying addition.
The present invention specifically excludes the alloying addition of the elements C, Ti, B and Zr. As has been discussed, the lOS3~82 13DV-6301 element C, although it plays a significant part in ordinary nickel-base superalloys in the carbide strengthening mechanism, can provide a source for crack initiation. Its elimination, except perhaps as an impurity in very small amounts, defines the alloy associated with the present invention as a different kind than the more classical types of nickel-base superalloys.
The elements Zr and B can function in nickel-base superalloys as grain boundary modifiers but have a tendency to lower melting temperature.
Therefore, Zr and B are not included as alloying additions in the present invention and are present only as residual elements which can be picked up during normal melting practices. For example, up to about 0. 03% Zr and up to about 0. 01% B, by weight, can be tolerated by the present invention without seriously affecting its characteristics.
Only a trace or very small amounts of Ti, for example up to about 1 atomic percent, can be tolerated by the present invention because of the tendency of Ti to form the gamma-gamma prime eutectic phase and to lower the melting temperature. During the evaluation of the present invention, a variety of Ni-base superalloys including varying amounts of Ti were made and tested. A typical one which forms the gamma-gamma prime eutectic in abundance is eXample 87, the composition of which is, in atomic percent, 6. 7 Co; 9 Cr; 1 Mo; 2. 4 W; 9. 3 Al; 5. 8 Ti; 1. 6 Ta; 0. 03 Zr; 0.17 B;
0. 25 ~ with the balance essentially Ni and incidental impurities. Particularly because of the presence of Ti and C, the alloy composition is outside of the scope o the present invention~ FIG. 3 of the drawings is a photomicrograph at 100 magnifications in the transverse direction of the example 87 after unidirectional solidification. FIG. 3 shows the presence of large amounts of the gamma-gamma prime eutectic which is the lighter constituent in the photomicrograph. The incipient melting temperature of example 87 is g _ :105348Z 1 3D~T -6301 about 2250F or at least about lOO~F lower than that of the present invention.
Although Ti generally is an essential element in other nickel-base superalloys as a strong gamma prime former, it has been eliminated from the present invention except in trace or residual amounts less than 1 at. %. Accordingly, a significant feature of the present invention is the substantial elimination of the elements C, Zr, B and Ti normally found in ordinary nickel-base superalloys.
Because of the virtual elimination of the strong gamma prime former Ti, a relatively large amount of Al, which in itself is a strong gamma prime former, is included in the alloy composition associated with the present invention, In this type of alloy, less than 5 at. % Al does not form sufficient gamma prime and therefore leads to a weak structure. Greater than about 16 at. % Al, even with a careful balance of other elements, tends to drop out NiAl or excess eutectic and in some alloys tends to reduce incipient melti~g temperature. In addition to its being a strong gamma prime former, Al also improves oxidation resistance. Its preferred range is 8-14 at. %.
Substituting for the eliminated Ti is the element V, a gamma prime former without titanium's tendency toward the formation of the gamma-gamma prime eutectic phase which can lower melting temperature. V also provides some solid solution strengthening. In atomic percent, V is included in the range of up to 10% although 1-7% is preferred. Greater than about 10%
will have a tendency toward the rejection of NiAl and thus dramatically reduce stress rupture properties. When higher strength is desired, it is specifically preferred that V be included in the range of about 4-7 at. ~o.
An important element which is required to be included in the present invention is Re for solid solution strengthening and precipitation hardening. It affects both the gamma prime precipitate as well as the gamma i(~53~ 13DV-6301 matrix. At least 0. S at. % Re, equivalent to at least about 1, 5% Re by weight,is required for its significant effect in strengthening the matrix, particularlyto increase high temperature stress rupture life. In addition, it also affects the gamma prime in that it has a tendency to force hardeners such as Ta and V into the gamma prime. In addition to this function, Re can substitute in amounts up to about 2. S at. % for such elements as W, Mn, Ta, Mo and Cr, all of which tend to partition between the gamma prime precipitate and the gamma matrix. Thus, Re is included in the present invention within the range of 0. 5-5 at. % and preferably in the range of 0. 5-3%. As shown by the examples of the following Table III, Re in the specific range of 0. 5-2 at. %
is particularly desirable for increasing high temperature stress rupture properties and while con~idering alloy cost. Comparison of example 123 with example 110 shows that the absence of Re is not compensated for by an increase in W to maintain the 1800F stress rupture properties of example 123.
10~348;~ `
TABLE III
Effect of Re on Properties Composition (Atomic %) _ Stress Rupture Life (hrs) Base: 3.5 Co, 12,7 Al, Balance Ni 5 Example Cr Ta V Re W1650F/60 ksi1800F/35 ksi 105 5.4 2,2 5.5 2.0 246 281 124 5.4 2.7 5.5 1.5 301 270 136 5.9 2.2 5.5 1.5 247 173 125 5.4 3.2 5.5 1.0 189 130 131 5.4 2.2 6.5 1.0 150 134 126 5.4 3.7 5.5 0.5 111 96 132 5.4 2.2 7.0 0.5 101 36 123 5.4 2.2 5.5 0.5 1.5 98 175 110 5.7 2.2 5.5 --- 2.1 110 96 1053~8i~
Ta can be included in the present invention up to 5 at. % and is preferably included in the range of 1-4 at. %. Ta in the type of alloy to which the present invention relates partitions between the gamma prime precipitate and the gamma matrix. Thus, it is both a gamma prime former as well as a solid solution strengthener. Also, it has a tendency to increase incipient melting temperature.
Two elements which act similarly to Ta are W and Mo.
Although W can be included up to about 5 at. %, it is preferred that such element be maintained in the range of up to about 2% for improved properties.
Mo, which can be included up to about 1 at. %, in the absence of Ti will partition to gamma prime. However, it has a tendency to impair corrosion and oxidation resistance. Therefore, it is included only up to about 1 at. %.
Required primarily for improvement in oxidation resistance is Cr which can be included in the range of about 4-11 at. % and preferably in the range of about 4-9 at. %. Less than 4% is insufficient for oxidation resistance; greater than 11% tends to introduce alloy instability. At such higher levels, the alloy is either too weak or is unstable. Therefore, it is preferred that Cr be included in the range of 4-9 at. % with higher amounts being tolerable provided other elements, within the range of the present invention, are balanced to avoid forcing the formation of NiAl or other mdesirable phases such as sigma, eta and mu. The effect of such unbalance is shown in the following Table IV.
~05348Z 13DV - 6301 TABLE IV
Effect of Re and Cr on Properties Composition (Atomic ~o~Stress Rupture Life (hrs) Base: 3.5 Co, Balance Ni 5 Example r Al Ta V Re1650F/60 ksi 1800F/35 ksi_ 136 5.9 12.7 2.25.5 1.5247 173 146 7.0 12,2 2.15.3 2.0174 202 142 8.0 12.7 2.25.5 1.0121 95 147 8.5 11.7 2.15.0 2.0140 247 143 9.0 12.7 2.25.5 1.0101 102 144 10.0 12.7 2.25.5 1.0 2 3 148 10.0 11.2 2.04.7 2.0 33 48 145 11.0 12.7 2.25.5 1.0 1 3 - l~L -Photomicrographic studies of the examples of Table IV showed that only examples 144, 145 and 148 exhibited the undesirable NiAl structure.
The dramatic difference in properties can be seen from the stress rupture data presented in Table IV. Referring to the drawings, FIG. 4 is a photomicrograph at 100 magnifications in the transverse direction of the structure of example 145 showing a large amount of the dark NiAl detrimental phase which produced the dramatic reduction in stress rupture properties in examples 144, 145 and 148 even though example 148 included 2 at. % Re.
For this reason, the present invention is characterized by the absence of NiAl in its microstructure which also has the aligned cellular dentrites.
The element Co can be included in the present invention as a substitute for nickel in an amount up to about 15 at. %. It has a slight tendency toward the increase of melting temperature and lowers the stacking fault energy. Preferably, Co is included in the range of about 3-8 at. %.
Mn and Rh can be included as partial substitutes for Re in the present invention. However, they are not as effective as is Re. Each of Mn and Rh can be included within the present invention in amounts up to 2.5 at. %
but preferably are included in amounts up to 1 at. % each. The effect of additions of Mn, Rh and Mo at various levels of Re is shown in Table V.
iQ5348Z 1 3DV- 63 01 .~
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In addition to a remarkable improvement in stress rupture properties, the present invention provides significant improvement in creep properties. This is shown in the data on which FIG. 5 is based, comparing example 106 with a known cast nickel-base superalloy now in production use in gas turbine engines and included within the scope of U. S. Patent 3, 615, 376 -Ross, issued October 26, 1971.
From all of these data, it can be seen that the present invention provides a different kind of alloy which is particularly useful in the formationof articles having improved high temperature properties as a result of the combination of the balance of elements and the processing to provide aligned cellular dendrites in the article's microstructure. Ordinary nickel-base superalloys include carbon which is then available for the formation of various types of carbides. The strength mechanism and microstructure of such ordinary alloy heavily involves carbide formation and accumulation at various points in the microstructure. The literature in respect to nickel-base superalloys includes very complete discussions of this type of microstructure and its problems and benefits based on carbides. Without carbon, there is defined a completely different kind of alloy, the properties of which depend on the gamma prime, gamma, eutectic and other phases, some of which can be detrimental or undesirable. For example, NiAl, which is sometimes called beta phase, is dramatically destructive toward stress rupture properties;the gamma-gamma prime eutectic tends to lower incipient melting temperature and hence it is to be maintained at as low a level as is practical. To obtain high temperature strength which otherwise has been provided by the absent carbides, the type of alloy involved with the present invention must include significantly larger or different alloying additions to strengthen both the gamma prime intermetallic precipitate as well as the gamma matrix while ~Q53~8;~
13DV-fi301 removing the tendency toward NiAl formation and reducing the gamma-gamma prime eutectic formation. Thus, the present invention adds as much A1 and C'r as possible while maintaining such stability and balancing the alloy's stability with other alloying additions to avoid the formation of NiA1.
The cast article of the present invention is characterized not only by its aligned cellular dendritic structure and the absence of carbides and NiAl, but also by the fact that it does not include alloying additions of Ti, Zr and B normally added to nickel-base superalloys. In addition> it includes relatively large amounts of Re which has been found to provide improved strength both for the gamma matrix as well as for the gamma prime precipitate. Because the alloy has a narrower solidus-liquidus range, it is easier to process by unidirectional solidification and therefore such processing can be conducted at higher rates. Its improved stress rupture properties are attained without a sacrifice of tensile properties which are as lS good or better than ordinary superalloy tensile strength and ductilities.
Although the present invention has been described in connection with specific examples and embodiments, it will be understood by those skilled in the art the variations and modifications of which the invention is capable within its broad scope.
More recent efforts in the development of nickel-base superalloys and their articles for use under strenuous operating conditions such as are found in gas turbine engines includes emphasis on composite eutectic alloys. Such alloys include reinforcing carbide members such as fibers which can be formed in situ during solidification of the alloy. One form of such solidification which ~as been used and has been widely reported iæ generally referred to as unidirectional solidification.
Creation of such carbide reinforced alloys obviously requires the addition of the element carbon. However, during the study of such alloys, it was recognized that detrimental interaction can occur at the interface between the carbide and the matrix. In addition, carbides can provide a source for crack initiation.
It has been recognized that the gamma prime former Ti, when included in a nickel-base superalloy structure, depresses the alloy's incipient melting temperature and tends to promote the formation of a eutectic phase for example, the gamma-gamma prime eutectic. With Ti, the incipient melting temperature is about 2250F.
Summary of the Invention It is a principal object of the present invention to provide an improved cast nickel-base superalloy article, the microstructure of which is substantially free of carbon, carbides, titanium and phases which are detrimental to high temperature strength properties.
lOS348Z 1 3DV-630 1 Another object is to provide a castable nickel-base superalloy sub6tantially free of carbon and titanium and which is particularly useful in the casting of unidirectionally solidified articles.
These and other objects and advantages will be more clearly understood from the following detailed description, the drawings and the examples all of which are intended to be typical of rather than in any way limiting on the scope of the present invention.
Briefly, the present invention, in one form, provides a cast nickel-base superalloy article the microstructure of which comprises aligned cellular dendrites and is further characterized by the substantial absence of the detrimental NiAl phase, carbon, carbides and Ti. The superalloy associated with the present invention consists, in atomic percent, essentially of 4-11 Cr, 5-16 Al, at least 0. 5 Re, up to about 10 V, up to about 15 Co, up to about 5 Ta, up to about 5 W, up to about 1 Mo, up to about 2. 5 Mn, up to about 2. 5 Rh, with the balance Ni and incidental impurities. Such incidental impurities may include Ti at less than 1 and C at less than 0.1 at. % which, by weight, is less than about 0. 017%. It is also preferred that the elements Zr and B be omitted from the composition, their presence being limited to those levels which result from normal pick-up of stray elements during melting and casting, for example up to about 0. 03% Zr and 0. 01% B by weight.
For comparison purposes, the approximate percent by weight equivalent of this form of the invention consists essentially of 3. 5-10 Cr; 2. 2-7. 2 Al; at least 1. 5 Re; up to about 8. 5 V; up to about 15 each of Co, Ta and W; up to about 1. 5 Mo; up to about 2. 5 Mn; up to about 4. 5 Rh; with the balance Ni and incidental impurities.
In a preferred form of the present invention, the composition, and atomic percent, consist essentially of 3-8 Co, 4-9 Cr, 8-14 Al, 1-4 Ta, 1053~8Z 1 3DV - 63 01 1-7 V, 0. 5-5 Re, up to about 2 W, up to about 1 each of Mo, Mn and Rh, with the balance essentially nickel and incidental impurities. For comparison purposes, the approximate percent by weight equivalent of this preferred form consists essentially of 3-8 Co; 3. 5-8 Cr; 3. 6-6. 3 A1; 3-12 Ta; 0. 8-6 V;1. 5-15 Re; up to about 6 W; up to about 1. 5 Mo; up to about 1 Mn; up to about 1. 8 Rh; with the balance Ni and incidental impurities.
Brief Description of the Drawings FIG. 1 is a photomicrographic view at 100 magnifications of the structure OI example 105 within the scope of the present invention showing the aligned cellular dendrites in the transverse directionand the absence of NiAl;
FIG. 2 is a photomicrographic view at 100 magnifications of the structure of example 105 within the scope of the present invention showing the aligned cellular dendrites in the longitudinal direction and the absence of 1 5 NiAl;
FIG. 3 is a photomicrographic view at 100 magnifications in the transverse direction of the alloy of example 87 outside the scope of the present invention showing the presence of abundant gamma-gamma prime eutectic phase;
FIG. 4 is a photomicrographic view at 100 magnifications in the transverse direction of the alloy of example 145 outside the scope of the present invention showing the presence of NiAl phase; and FIG. 5 is a graphical comparison of creep properties.
Description of the Preferred Embodiments In order to provide an improved nickel-base superalloy article useful under such strenuous operating conditions as are found in the turbine section of a modern gas turbine engine, and to remove the carbide 1053~8Z
strengthening mechanism from the alloy of such article, it is necessary to design such alloy with significantly larger amounts of other strengthening elements. The principal strengthening mechanism remaining after carbide elimination is the gamma prime phase, which is predominantly Ni3Al, in the gamma matrix, which is predominantly nickel. However, the gamma prime and the gamma phases can be strengthened with the addition of alloying elements. One of the problems which exists in the addition of significantly higher levels of alloying elements is that the detrimental NiAl phase can be forced to form, particularly at higher Al values. Further, the combination of elements can move the alloy into that portion of the alloy's phase diagram which causes the formation of gamma-gamma prime eutectic. The NiAl causes a significant and dramatic reduction in high temperature properties and the gamma-gamma prime eutectic lowers the incipient melting point of the alloy.
The present invention defines a unique castable nickel-base superalloy which is not strengthened by any carbide mechanism and which includes a balance of alloying elements providing strength characteristics even greater than the carbide strengthened type superalloy structures. At the same time, its structure is extremely uniform, includes substantially no NiAl phase and avoids the gamma-gamma prime eutectic. As a result, the incipient melting temperature of the alloy associated with the present irnvention is at least about 100F higher than an ordinary superalloy's incipient melting temperature of about 2250~F. In addition, through the inclusion of a balance of elements which strengthen the gamma prime precipitate phase, the gamma prime solution temperature is at least 100 higher than that of the ordinary superalloy. Furthermore, the alloy is uniquely adapt.od for unidirectional solidification to provide that structure l(~S348'~
defined as an aligned cellular dendritic structure. Thus, an article having such a structure and made from the composition provided by the present in~rention has a higher temperature operating capability as well as over-temperature protection in that the chances of causing incipient melting of the article are reduced.
The present invention will be more fully understood from the following discussion of representative examples of alloy forms studied during the evaluation of the present invention. Such examples are grouped for ready comparison but are not intended to be limitations on the invention's scope.
The alloy associated with the present invention, in atomic percent, consists essentially of 4-11 Cr, 5-16 Al, at least 0. 5 Re, up to about lOV, up to about 15 Co, up to about 5 each of Ta and W, up to about 1 Mo, up to about 2. 5 each of Mn and Rh, with the balance essentially nickel and incidental impurities. However, the preferred form of such alloy, in atomic percent, consists essentially of 3-8 Co, 4-9 Cr, 8-14 Al, 1-4 Ta, 1-7 V, 0. 5-5 and more preferably 0.5 - 3 Re, up to about 2 W, up to about 1 each of Mo, Mn and Rh, with the balance essentially Ni and incidental impurities. The following Table I lists the compositions of selected forms of such alloy within the preferred range of the present invention and Table II
lists some of each form's mechanical property data. None of the elements C, Ti, B or Zr, usually found in nickel-base superalloys, were added and are to be specifically avoided, except in impurity amounts, according to the present invention. Unless otherwise specified throughout this specification, all compositions are in atomic percent.
~05348Z 13DV-6301 TAB LE I -Preferred form of Invention Composition (Atomic ~o) Balance Ni Example Co Cr Al Ta V Re W Mo Mn Rh 105 3.5 5.4 12.7 2.25.5 2.0 106 3.5 5.4 12.8 1.45.5 2.0 0.9 118 3.5 5.4 12.7 2.25.5 1.5 0.5 122 3.5 5.4 12.7 2.25.5 1.0 1.0 123 3.5 5.4 12.7 2.25.5 0.5 1.5 124 3.5 5.4 12.7 2.75.5 1.5 125 3.5 5.4 12.7 3.25.5 1.0 127 3.5 5.4 12.7 2.25.5 1.5 0.5 128 3,5 5.4 12.7 2.25.5 1.0 1.0 133 3.5 5.4 12.7 2.25.5 1.5 0.5 134 3.5 5.4 12.7 2.25.5 1.0 1.0 136 3.5 5.9 12.7 2.25.5 1.5 146 3.5 7.0 12.2 2.15.3 2.0 147 3.5 8.5 11.7 2.15.0 2.0 l~S3~8Z 13~V-6301 TABLE II
Mechanical Properties of Preferred Form Stress Rupture _ Tensile (1200F) 1650F/60 ksi 1800~F/35 ksiUltimateYield R.A.
Example Life(hrs) R. A. Life(hrs) R. A.(ksi)(ksi) (%) As used in tables herein, the terms "ksi" means "thousands of pounds per square inch" and "RA" means "Reduction in Area". All of the data were obtained by testing in air under the conditions identified.
In order to provide cast stress rupture, tensile and creep specimens for each of the alloys evaluated in connection with the present invention, each alloy form was cast and unidirectionally solidified at the rate of about 20 inches per hour to create the aligned cellular dendritic structure which characterizes the article of the present invention. Such structure is aligned predominantly in the ~001> direction, which is equivalent to the<100>
and ~Ol(~directions. Photomicrographic studies of each of the alloys in Table I showed no NiAl phase present. Referring to the drawings, FIGS. 1 and 2 are photomicrographs at 100 magnifications of example 105, typical of the microstructure of the present invention. They show the aligned cellular dendritic structure which resulted from unidirectional solidification, FIG. 1 being in the transverse direction and FIG. 2 being in the longitudinal direction.
The elongated dendrites are more clearly shown in FIG. 2. The absence of the dark NiAl phase, shown in FIG. 4,to be discussed later, is particularly evident in FIGS. 1 and 2.
As was mentioned before, NiAl phase is dramatica~ly detrimental to stress rupture properties and hence one of the important characteristics of the present invention is that no NiAl is present in the alloy's microstructure. The data of Table II clearly shows the significantly improved stress rupture properties of the present invention at no sacrifice of tensile proper~ies even though no carbide strengthening is present and the gamma prime strengthener Ti has not been included as an alloying addition.
The present invention specifically excludes the alloying addition of the elements C, Ti, B and Zr. As has been discussed, the lOS3~82 13DV-6301 element C, although it plays a significant part in ordinary nickel-base superalloys in the carbide strengthening mechanism, can provide a source for crack initiation. Its elimination, except perhaps as an impurity in very small amounts, defines the alloy associated with the present invention as a different kind than the more classical types of nickel-base superalloys.
The elements Zr and B can function in nickel-base superalloys as grain boundary modifiers but have a tendency to lower melting temperature.
Therefore, Zr and B are not included as alloying additions in the present invention and are present only as residual elements which can be picked up during normal melting practices. For example, up to about 0. 03% Zr and up to about 0. 01% B, by weight, can be tolerated by the present invention without seriously affecting its characteristics.
Only a trace or very small amounts of Ti, for example up to about 1 atomic percent, can be tolerated by the present invention because of the tendency of Ti to form the gamma-gamma prime eutectic phase and to lower the melting temperature. During the evaluation of the present invention, a variety of Ni-base superalloys including varying amounts of Ti were made and tested. A typical one which forms the gamma-gamma prime eutectic in abundance is eXample 87, the composition of which is, in atomic percent, 6. 7 Co; 9 Cr; 1 Mo; 2. 4 W; 9. 3 Al; 5. 8 Ti; 1. 6 Ta; 0. 03 Zr; 0.17 B;
0. 25 ~ with the balance essentially Ni and incidental impurities. Particularly because of the presence of Ti and C, the alloy composition is outside of the scope o the present invention~ FIG. 3 of the drawings is a photomicrograph at 100 magnifications in the transverse direction of the example 87 after unidirectional solidification. FIG. 3 shows the presence of large amounts of the gamma-gamma prime eutectic which is the lighter constituent in the photomicrograph. The incipient melting temperature of example 87 is g _ :105348Z 1 3D~T -6301 about 2250F or at least about lOO~F lower than that of the present invention.
Although Ti generally is an essential element in other nickel-base superalloys as a strong gamma prime former, it has been eliminated from the present invention except in trace or residual amounts less than 1 at. %. Accordingly, a significant feature of the present invention is the substantial elimination of the elements C, Zr, B and Ti normally found in ordinary nickel-base superalloys.
Because of the virtual elimination of the strong gamma prime former Ti, a relatively large amount of Al, which in itself is a strong gamma prime former, is included in the alloy composition associated with the present invention, In this type of alloy, less than 5 at. % Al does not form sufficient gamma prime and therefore leads to a weak structure. Greater than about 16 at. % Al, even with a careful balance of other elements, tends to drop out NiAl or excess eutectic and in some alloys tends to reduce incipient melti~g temperature. In addition to its being a strong gamma prime former, Al also improves oxidation resistance. Its preferred range is 8-14 at. %.
Substituting for the eliminated Ti is the element V, a gamma prime former without titanium's tendency toward the formation of the gamma-gamma prime eutectic phase which can lower melting temperature. V also provides some solid solution strengthening. In atomic percent, V is included in the range of up to 10% although 1-7% is preferred. Greater than about 10%
will have a tendency toward the rejection of NiAl and thus dramatically reduce stress rupture properties. When higher strength is desired, it is specifically preferred that V be included in the range of about 4-7 at. ~o.
An important element which is required to be included in the present invention is Re for solid solution strengthening and precipitation hardening. It affects both the gamma prime precipitate as well as the gamma i(~53~ 13DV-6301 matrix. At least 0. S at. % Re, equivalent to at least about 1, 5% Re by weight,is required for its significant effect in strengthening the matrix, particularlyto increase high temperature stress rupture life. In addition, it also affects the gamma prime in that it has a tendency to force hardeners such as Ta and V into the gamma prime. In addition to this function, Re can substitute in amounts up to about 2. S at. % for such elements as W, Mn, Ta, Mo and Cr, all of which tend to partition between the gamma prime precipitate and the gamma matrix. Thus, Re is included in the present invention within the range of 0. 5-5 at. % and preferably in the range of 0. 5-3%. As shown by the examples of the following Table III, Re in the specific range of 0. 5-2 at. %
is particularly desirable for increasing high temperature stress rupture properties and while con~idering alloy cost. Comparison of example 123 with example 110 shows that the absence of Re is not compensated for by an increase in W to maintain the 1800F stress rupture properties of example 123.
10~348;~ `
TABLE III
Effect of Re on Properties Composition (Atomic %) _ Stress Rupture Life (hrs) Base: 3.5 Co, 12,7 Al, Balance Ni 5 Example Cr Ta V Re W1650F/60 ksi1800F/35 ksi 105 5.4 2,2 5.5 2.0 246 281 124 5.4 2.7 5.5 1.5 301 270 136 5.9 2.2 5.5 1.5 247 173 125 5.4 3.2 5.5 1.0 189 130 131 5.4 2.2 6.5 1.0 150 134 126 5.4 3.7 5.5 0.5 111 96 132 5.4 2.2 7.0 0.5 101 36 123 5.4 2.2 5.5 0.5 1.5 98 175 110 5.7 2.2 5.5 --- 2.1 110 96 1053~8i~
Ta can be included in the present invention up to 5 at. % and is preferably included in the range of 1-4 at. %. Ta in the type of alloy to which the present invention relates partitions between the gamma prime precipitate and the gamma matrix. Thus, it is both a gamma prime former as well as a solid solution strengthener. Also, it has a tendency to increase incipient melting temperature.
Two elements which act similarly to Ta are W and Mo.
Although W can be included up to about 5 at. %, it is preferred that such element be maintained in the range of up to about 2% for improved properties.
Mo, which can be included up to about 1 at. %, in the absence of Ti will partition to gamma prime. However, it has a tendency to impair corrosion and oxidation resistance. Therefore, it is included only up to about 1 at. %.
Required primarily for improvement in oxidation resistance is Cr which can be included in the range of about 4-11 at. % and preferably in the range of about 4-9 at. %. Less than 4% is insufficient for oxidation resistance; greater than 11% tends to introduce alloy instability. At such higher levels, the alloy is either too weak or is unstable. Therefore, it is preferred that Cr be included in the range of 4-9 at. % with higher amounts being tolerable provided other elements, within the range of the present invention, are balanced to avoid forcing the formation of NiAl or other mdesirable phases such as sigma, eta and mu. The effect of such unbalance is shown in the following Table IV.
~05348Z 13DV - 6301 TABLE IV
Effect of Re and Cr on Properties Composition (Atomic ~o~Stress Rupture Life (hrs) Base: 3.5 Co, Balance Ni 5 Example r Al Ta V Re1650F/60 ksi 1800F/35 ksi_ 136 5.9 12.7 2.25.5 1.5247 173 146 7.0 12,2 2.15.3 2.0174 202 142 8.0 12.7 2.25.5 1.0121 95 147 8.5 11.7 2.15.0 2.0140 247 143 9.0 12.7 2.25.5 1.0101 102 144 10.0 12.7 2.25.5 1.0 2 3 148 10.0 11.2 2.04.7 2.0 33 48 145 11.0 12.7 2.25.5 1.0 1 3 - l~L -Photomicrographic studies of the examples of Table IV showed that only examples 144, 145 and 148 exhibited the undesirable NiAl structure.
The dramatic difference in properties can be seen from the stress rupture data presented in Table IV. Referring to the drawings, FIG. 4 is a photomicrograph at 100 magnifications in the transverse direction of the structure of example 145 showing a large amount of the dark NiAl detrimental phase which produced the dramatic reduction in stress rupture properties in examples 144, 145 and 148 even though example 148 included 2 at. % Re.
For this reason, the present invention is characterized by the absence of NiAl in its microstructure which also has the aligned cellular dentrites.
The element Co can be included in the present invention as a substitute for nickel in an amount up to about 15 at. %. It has a slight tendency toward the increase of melting temperature and lowers the stacking fault energy. Preferably, Co is included in the range of about 3-8 at. %.
Mn and Rh can be included as partial substitutes for Re in the present invention. However, they are not as effective as is Re. Each of Mn and Rh can be included within the present invention in amounts up to 2.5 at. %
but preferably are included in amounts up to 1 at. % each. The effect of additions of Mn, Rh and Mo at various levels of Re is shown in Table V.
iQ5348Z 1 3DV- 63 01 .~
6q ~1 c~ C~ _~ N u~
~; d~
_ O
bq L C'~ O C~
o ~1 o l u~
m~
¢ ~ o, u~
E ~ o ~1 .,.. .
P~ V I ~ u~ u~ O ~ u~ O u~
~ " _~ _, o _, ~ o ~ _~ o In ,_, o~ a) o t~
m ~ ~
U~ O
In addition to a remarkable improvement in stress rupture properties, the present invention provides significant improvement in creep properties. This is shown in the data on which FIG. 5 is based, comparing example 106 with a known cast nickel-base superalloy now in production use in gas turbine engines and included within the scope of U. S. Patent 3, 615, 376 -Ross, issued October 26, 1971.
From all of these data, it can be seen that the present invention provides a different kind of alloy which is particularly useful in the formationof articles having improved high temperature properties as a result of the combination of the balance of elements and the processing to provide aligned cellular dendrites in the article's microstructure. Ordinary nickel-base superalloys include carbon which is then available for the formation of various types of carbides. The strength mechanism and microstructure of such ordinary alloy heavily involves carbide formation and accumulation at various points in the microstructure. The literature in respect to nickel-base superalloys includes very complete discussions of this type of microstructure and its problems and benefits based on carbides. Without carbon, there is defined a completely different kind of alloy, the properties of which depend on the gamma prime, gamma, eutectic and other phases, some of which can be detrimental or undesirable. For example, NiAl, which is sometimes called beta phase, is dramatically destructive toward stress rupture properties;the gamma-gamma prime eutectic tends to lower incipient melting temperature and hence it is to be maintained at as low a level as is practical. To obtain high temperature strength which otherwise has been provided by the absent carbides, the type of alloy involved with the present invention must include significantly larger or different alloying additions to strengthen both the gamma prime intermetallic precipitate as well as the gamma matrix while ~Q53~8;~
13DV-fi301 removing the tendency toward NiAl formation and reducing the gamma-gamma prime eutectic formation. Thus, the present invention adds as much A1 and C'r as possible while maintaining such stability and balancing the alloy's stability with other alloying additions to avoid the formation of NiA1.
The cast article of the present invention is characterized not only by its aligned cellular dendritic structure and the absence of carbides and NiAl, but also by the fact that it does not include alloying additions of Ti, Zr and B normally added to nickel-base superalloys. In addition> it includes relatively large amounts of Re which has been found to provide improved strength both for the gamma matrix as well as for the gamma prime precipitate. Because the alloy has a narrower solidus-liquidus range, it is easier to process by unidirectional solidification and therefore such processing can be conducted at higher rates. Its improved stress rupture properties are attained without a sacrifice of tensile properties which are as lS good or better than ordinary superalloy tensile strength and ductilities.
Although the present invention has been described in connection with specific examples and embodiments, it will be understood by those skilled in the art the variations and modifications of which the invention is capable within its broad scope.
Claims
1. A cast Ni-base superalloy article the micro-structure of which comprises aligned cellular dendrites and is characterized by the substantial absence of NiAl, carbon, carbides and Ti, the superalloy consisting, in atomic percent, essentially of 4-11 Cr, 5-16 Al, about 0.5-5 Re, up to about 10V, up to about 15 Co, up to about 5 Ta, up to about 5 W, up to about 1 Mo, up to about 2.5 Mn, up to about 2.5 Rh, with the balance essentially nickel and incidental impurities.
2. The article of claim 1 in which the superalloy consists, in atomic percent, essentially of 3-8 Co, 4-9 Cr, 8-14 Al, 1-4 Ta, 1-7 V, 0.5-5 Re, up to about 2 W, up to about 1 Mo, up to about 1 Mn, up to about 1 Rh, whith the balance essentially nickel and incidental impurities.
3. The article of claim 2 in which the V is 4-7 at.
percent and the Re is 0.5-3 at. percent.
4. The article of claim 3 in which the superalloy consists, in atomic percent, essentially of 3-4 Co, 5-9 Cr, 11-13 A1, 1-3 Ta, 5-6 V, 0.5-2 Re, up to 1.5 W, up to 1 Mo, up to 0.5 Mn, with the balance nickel and incidental impurities.
5. A cas Ni-base superalloy characterized by the substantial absence of NiAl, carbon, carbides and Ti and consisting, in atomic percent, essentially of 4-11 Cr, 5-16 Al, about 0.5 5 Re, up to about 10 V, up to about 15 Co, up to about 5 Ta, up to about S W, up to about 1 Mo, up to about 2.5 Mn, up to about 2.5 Rh, with the balance essentially nickel and incidental impurities.
6. The alloy of claim 5 consisting, in atomic percent, essentially of 3-8 Co, 4-9 Cr, 8-14 Al, 1-4 Ta, 1-7V, 0.5-5 Re, ? to about 2 W, up to about 1 Mo, up to about 1 Mn, up to about 1 Rh, with the balance essentially nickel and incidental impurities.
7. The alloy of claim 6 in which the V is 4-7 at. % and the Re is 0. 5-3 at. %.
8. The alloy of claim 7 consisting, in atomic percent, essentially of 3-4 Co, 5-9 Cr, 11-13 Al, 1-3 Ta, 5-6 V, 0. 5-2 Re, up to
1. 5 W, up to 1 Mo, up to 0. 5 Mn, with the balance nickel and incidental impurities .
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US426092A US3887363A (en) | 1973-12-18 | 1973-12-18 | Nickel-base superalloy cast article |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1053482A true CA1053482A (en) | 1979-05-01 |
Family
ID=23689251
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA215,680A Expired CA1053482A (en) | 1973-12-18 | 1974-12-09 | Nickel-base superalloy cast article |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US3887363A (en) |
| JP (1) | JPS5095122A (en) |
| BE (1) | BE823437A (en) |
| CA (1) | CA1053482A (en) |
| DE (1) | DE2458540A1 (en) |
| FR (1) | FR2254651B1 (en) |
| GB (1) | GB1473134A (en) |
| IT (1) | IT1027700B (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4169742A (en) * | 1976-12-16 | 1979-10-02 | General Electric Company | Cast nickel-base alloy article |
| GB1562082A (en) * | 1977-10-17 | 1980-03-05 | Gen Electric | Nickel-base olloys |
| WO1979000343A1 (en) * | 1977-12-05 | 1979-06-14 | Secr Defence | Improvements in or relating to nickel-,cobalt-,and iron based alloys |
| SE452633B (en) * | 1978-03-03 | 1987-12-07 | Johnson Matthey Co Ltd | Nickel base alloy with gamma primer matrix |
| JPS5814016B2 (en) * | 1978-03-31 | 1983-03-17 | 株式会社日立製作所 | Substrate metal plate material for directly heated oxide cathode |
| US4313760A (en) * | 1979-05-29 | 1982-02-02 | Howmet Turbine Components Corporation | Superalloy coating composition |
| US4339509A (en) | 1979-05-29 | 1982-07-13 | Howmet Turbine Components Corporation | Superalloy coating composition with oxidation and/or sulfidation resistance |
| US4765850A (en) * | 1984-01-10 | 1988-08-23 | Allied-Signal Inc. | Single crystal nickel-base super alloy |
| CA1315572C (en) * | 1986-05-13 | 1993-04-06 | Xuan Nguyen-Dinh | Phase stable single crystal materials |
| US6468368B1 (en) * | 2000-03-20 | 2002-10-22 | Honeywell International, Inc. | High strength powder metallurgy nickel base alloy |
| US7641985B2 (en) * | 2004-06-21 | 2010-01-05 | Siemens Energy, Inc. | Boron free joint for superalloy component |
| JP5146867B2 (en) * | 2006-08-18 | 2013-02-20 | 独立行政法人物質・材料研究機構 | Heat resistant material with excellent high temperature durability |
| US8216509B2 (en) * | 2009-02-05 | 2012-07-10 | Honeywell International Inc. | Nickel-base superalloys |
| JP6016016B2 (en) | 2012-08-09 | 2016-10-26 | 国立研究開発法人物質・材料研究機構 | Ni-based single crystal superalloy |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3526499A (en) * | 1967-08-22 | 1970-09-01 | Trw Inc | Nickel base alloy having improved stress rupture properties |
-
1973
- 1973-12-18 US US426092A patent/US3887363A/en not_active Expired - Lifetime
-
1974
- 1974-07-05 GB GB2991674A patent/GB1473134A/en not_active Expired
- 1974-12-09 CA CA215,680A patent/CA1053482A/en not_active Expired
- 1974-12-11 DE DE19742458540 patent/DE2458540A1/en not_active Withdrawn
- 1974-12-16 IT IT30578/74A patent/IT1027700B/en active
- 1974-12-17 FR FR7441455A patent/FR2254651B1/fr not_active Expired
- 1974-12-17 BE BE151573A patent/BE823437A/en unknown
- 1974-12-17 JP JP49144123A patent/JPS5095122A/ja active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| US3887363A (en) | 1975-06-03 |
| IT1027700B (en) | 1978-12-20 |
| BE823437A (en) | 1975-04-16 |
| GB1473134A (en) | 1977-05-11 |
| FR2254651A1 (en) | 1975-07-11 |
| DE2458540A1 (en) | 1975-06-19 |
| JPS5095122A (en) | 1975-07-29 |
| FR2254651B1 (en) | 1977-07-08 |
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