JPH0339435A - Production and product of fatigue crack- resisting nickel-base superalloy - Google Patents

Abstract

PURPOSE: To produce a Ni base superalloy excellent in fatigue crack resistance by preparing a Ni base superalloy contg. specified ratios of Co, Cr, Mo, Al, Ti, Ta, Nb, Re, Hf, Zr, V, C, B, W and Y at a specified cooling rate.

CONSTITUTION: A Ni superalloy contg., by weight, 12 to 18% Co, 7 to 13% Cr, 2 to 4% Mo, 3 to 5% Al, 3.5 to 5.5% Ti, 1 to 2% Ta, 3 to 5% Nb, 0.0 to 3.0% Re, 0.0 to 0.75% Hf, 0.00 to 0.10% Zr, 0.0 to 2.0% V, 0.0 to 0.20% C, 0.01 to 0.10% B, 0.0 to 1.0% W, 0.0 to 0.1% Y, and the balance Ni is produced at a cooling rate of about ≤600°F/min. In this way, a Ni base superalloy improved in resistance to the generation of cracks can be obtd.

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Background of the Invention It is well known that nickel-based superalloys are widely used in environments requiring high performance. Such an alloy is
Jet engines, land gas turbines and 1000°
It has been widely used in other engines where high strength and other desirable physical properties must be maintained at temperatures above F.F.

Many of these alloys have various volume fractions of γ′
Contains precipitates. This γ' precipitate is responsible for the high performance properties of such alloys at high service temperatures.

The characteristics of the phase chemistry of γ′ precipitates are characterized by holes (E, L, Ha
ll), Kouh (Y, M, Kouh) and Chang (K
, M. Chang), American Society of Electron Microscopy Box 41st Pension Bulletin, August 1983.
edings or41st Annual Meet
lng of' Electron Mlcrosco
pySocloty or America) No. 248
“Phase Chemistry of Precipitation Strengthened Superalloys” on page
mistries ln Proclpitatlon
-8trengthonlng 5upperalloy
) is discussed in more detail in J.

U.S. Patent Nos. 2,570.193 and 2,621.12
No. 2, No. 3.046.108, No. 3゜061.426
No. 3,151,981, No. 3.166.412, No. 3.322.534, No. 3,343,950,
No. 3,575.734, No. 3.576.861, No. 4. 207. No. 098 and No. 4,336,312
No. 6, No. 1, Vol. These patents are representative of the many alloying developments reported to date, in which alloy systems with different physical and mechanical properties are developed to capture different functional relationships between elements. The same elements are combined in different ways to form the resulting phases. However, despite the abundance of data available on nickel-based alloys, when known elements are used in combination at certain concentrations to form alloys, such combinations are widely accepted in the industry. Even if it falls within the scope of the teaching,
In particular, it is difficult to predict with any degree of accuracy the physical and mechanical properties that such alloys will exhibit when they are processed using heat treatments different from those previously used. This is still not possible even for those skilled in the art.

An increasingly important and recognized problem with many such nickel-based superalloys is that they are prone to cracking (or cracking) during manufacturing or use, and that these cracks are often used in gas turbines. This means that they can actually propagate or elongate under stress during the use of the alloy in structures such as jet engines and the like.

Propagation and expansion of cracks can result in component destruction or other failure. The consequences of failure of moving mechanical parts due to crack initiation and propagation are well understood. Jet engines can pose a particularly serious danger.

However, until recent research, it was not very well understood that crack initiation and propagation in structures made of superalloys is caused by the same mechanism,
They are not simple phenomena that occur and propagate at the same speed and according to the same criteria. in contrast,
It is generally accepted that crack initiation and propagation and cracking phenomena are complex, and important new information has been accumulated in recent years regarding the interrelationship between such propagation and stress application. . How long a stress is applied to a member before it propagates or propagates, the intensity of the stress, the rate at which the stress is applied or removed from the member, and the effect of the plan to apply this stress are The US National Aeronautics and Space Administration (N
ational Air.

naut[cs and 5pace Adsinls
It was not well understood in the industry until some research was done under contract with tratlon. This work is reported in technical report NASA CR-165123. This report was published by the National Aeronautics and Space Administration in August 1980.
Cowles), Warren (J.R. Warren)
) and Hauke, P., “Evaluation of the cyclical behavior of aircraft turbine disk alloys (Evalu
ation of the Cycle Beha
vior of Aircraft Turblne
Disk Al1oys) J Part ■, considered the final report, was submitted to the US National Aeronautics and Space Administration (National Aeronautics and Space Administration).
ronautics and 5pace Ad
NASA Lewis Research Center
nter), created for contract NAS3-21379.

A key finding of this NASA-sponsored study is the fatigue phenomenon-based propagation velocity, or fatigue crack propagation (F CP
) is not necessarily uniform depending on the applied stress and how it is applied. Also, more importantly, it has been discovered that fatigue crack propagation actually varies with the frequency with which stress is applied to the member in a manner that propagates the crack. Even more surprising, a significant finding of the NASA-sponsored study is that applying stress at a lower frequency than the high frequency used in previous studies actually increases crack propagation rates. In other words,
This NASA study confirmed that fatigue crack propagation is time dependent. Furthermore, it has been found that the time dependence of this fatigue crack propagation depends not only on the frequency, but also on the length of time that the member is held under stress, that is, the so-called holding time.

After demonstrating abnormally increased fatigue crack propagation at this lower stress frequency, industry believes this newly discovered phenomenon could lead to the use of nickel-based superalloys in stressed components of turbines and aircraft engines. It was believed that it represented the ultimate limit of sexuality, and that every design effort must be made to circumvent this problem.

However, it has been discovered that it is possible to construct nickel-based superalloy components with significantly reduced crack propagation rates and good high temperature strength for use at high stresses in turbines and aircraft engines.

It is known that the most desired properties of superalloys are those required for jet engine construction.

Among the required properties, the combination of properties required varies depending on the various elements of the engine, but
Typically, the requirements for the moving parts of an engine are greater and more demanding than those for the fixed parts.

Because certain properties are not available in cast alloy materials, parts may have to be manufactured by powder metallurgy techniques. However, one of the limitations associated with using powder metallurgy techniques in the manufacture of moving parts for jet engines is the issue of powder purity. If the powder contains impurities such as small ceramic particles or oxides,
Where the particles are located in the moving part is a potential weak point for crack initiation. Such weak points are essentially potential cracks. The possible existence of such latent cracks makes the problem of reducing and inhibiting the rate of crack propagation all the more important. The inventors have discovered that it is possible to suppress crack propagation by applying both alloy composition adjustment and the manufacturing method of such metal alloys.

The present invention provides a superalloy that can be produced using powder metallurgy techniques. Also provided is a method of processing this superalloy to produce a material that has an excellent combination of properties for use in advanced engine discs.

Properties traditionally required for materials used for disk materials include high tensile strength and high stress fracture strength. Additionally, the alloys of the present invention exhibit the desirable property of resisting time-dependent crack growth propagation.

Resistance to such crack growth is essential to the low cycle fatigue (LCF) life of the component.

As alloy products for use in turbines and jet engines have been developed, it has become clear that various properties are required for the parts used in various parts of engines and turbines. In the case of jet engines, the requirements placed on more advanced aircraft engine materials continue to become more stringent as aircraft engine performance requirements increase. This requirement is substantiated, for example, by the fact that many blade alloys exhibit very good high temperature properties in the cast state. However, direct conversion of cast blade alloys to disk material alloys is highly unlikely, as blade material alloys exhibit insufficient strength at intermediate temperatures. Additionally, blade alloys have proven to be extremely difficult to forge, and forging has proven desirable for producing disks from disk alloys. Furthermore, the crack growth resistance of the disk alloy has not been evaluated. therefore,
It is always desirable to improve the strength and temperature performance of disk alloys as part of special alloys used in aircraft engines in order to increase engine efficiency and further improve performance.

Therefore, what was needed in carrying out the research that led to the present invention was the development of a disk alloy with low or moderate time dependence of fatigue crack propagation and with high resistance to fatigue crack initiation. there were. In addition, there was a need for a balance of properties, especially tensile, creep and fatigue properties. What was further needed was the strengthening of established alloy systems with respect to inhibiting crack growth phenomena.

In the development of the superalloy composition and processing method thereof of the present invention, attention is paid to fatigue properties, and in particular, the time dependence of crack growth is addressed.

It is known that the rate of crack growth, or crack propagation, in high strength alloy bodies is dependent on the applied stress (σ) and the crack length (a). These two factors are combined by fracture mechanics into a single crack growth driving force, the stress factor.
y factor ) becomes K. This factor has σJi
is proportional to. Under fatigue conditions, this stress intensity during a fatigue cycle can be assumed to consist of two components: a repetitive component and a static component. The former represents the difference between n and the maximum change in cyclic stress (ΔK), ie, K11ax. At moderate temperatures, crack growth is primarily dependent on the cyclic stress (ΔK) until static fracture toughness KIC is achieved.
) is determined by The crack growth rate is mathematically da/
It is expressed as dN ( A smaller repetition frequency may result in a faster crack growth rate.This undesirable time for fatigue crack propagation, this behavior can be seen in most existing high-strength superalloys. Adding to the complexity of time-dependent phenomena, increasing the temperature above a certain point
A crack can grow under static stress of some intensity with no repetitive component (i.e., part of Δ). The design goal is to find a value of d a /d N that is as small as possible and as time-independent as possible. The components of the stress intensity are the stress intensity of crack growth, both repetitive and static;
That is, they can interact with each other in a certain temperature range as a function of Δ and K.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, one object of the present invention is to provide a nickel-based superalloy product that is more resistant to cracking.

Another object is to provide a method for reducing the tendency of established known nickel-based superalloys to crack.

Another object is to provide an article that is more resistant to fatigue crack propagation when used under repeated high stresses.

Yet another object is to provide compositions and methods that enable nickel-based superalloys to be rendered resistant to cracking under repeated stresses over a range of frequencies.

Some of the other objectives will be apparent from the description below, and some will be pointed out below.

In one of its boat fishing aspects, the object of the present invention is to
This can be achieved by providing a composition having the following general composition.

Component Concentration in composition (wt%) (lower limit amount) ~
(Upper limit Q) Ni Balance Co 12-18 Cr 7-13 Mo 2-4 AI 3-5 Ti 3.5-5.5 Ta 1-2 Nb 3-5 Zr 0.0-0.10 V 0. O~2.0 CO00~0.20 Bo, 0~0.10 WO10~1.0 Another object of the present invention is to provide a composition having the following general composition. This can be achieved by

Component Concentration in composition (wt%) (lower limit amount) ~
(Upper limit amount) NL remaining Co 12-18 Cr 7-13 Mo 2-4 AI 3-5 Ti 3.5-5.5 Ta 1-2 Nb 3-5 Re 0.0-3.0 Hf 0.0 ~0.75 2r 0.0~0.10 vO90~2.0 CO10~0.20 Bo, 0~0.10 WO90~1,0 YO0θ~0.10° For detailed explanation below, please refer to the attached drawings. It will be easier to understand if you refer to it.

DETAILED DESCRIPTION OF THE INVENTION By studying currently commercially available alloys used in structures requiring high strength at high temperatures, the inventors have discovered that conventional alloys have a pattern. This pattern is similar to the final report NASA CR-1 mentioned above.
This is based on plotting data in No. 65123 using a method devised by the present inventor. The inventor is 19
Data from this 1980 NASA report was plotted using the parameters shown in Figure 1. As is clear from FIG. 1, these data are arranged almost diagonally.

In FIG. 1, crack growth rate (in/cycle) is plotted against ultimate tensile strength (ksi). Individual alloys are indicated on this graph by a plus (+) symbol, which represents the corresponding property of crack growth at the ultimate tensile strength (ksi) characteristic of each alloy. Shows speed (inch/cycle). As you can see, the straight line indicating the residence time of 900 seconds is
A characteristic relationship between crack growth rate and ultimate tensile strength of these conventionally known alloys is shown. At the bottom of this graph, similar data points corresponding to the displayed ten points are shown for crack propagation rate tests conducted at 0.33 hertz (Hz), or in other words, at a higher frequency. . The data shown as diamonds lies in the region along the line labeled 0.33 Hz for each alloy shown at the top of this graph.

As is clear from Figure 1, there is no alloy composition with the coordinates in the lower right corner of this graph for long residence times. In fact, all of the data points for the longer dwell time crack growth tests are along the diagonal of this graph, so any alloy composition that is formed will fall somewhere along the diagonal of this graph. In other words, it appeared impossible to find an alloy composition that had both high ultimate tensile strength and low crack growth rate at long residence times according to the parameters plotted in Figure 1. .

However, the inventors have discovered that it is possible to produce alloys with compositions that are capable of achieving a unique combination of high ultimate strength and low crack growth rates.

One of the conclusions reached hypothetically by the inventors was that chromium concentration could have some effect on the crack growth rate of various alloys.

For this reason, the present inventor found that the crack growth rate is affected by the chromium content.
i (wt%) was plotted. The results of this plot are shown in FIG. In this figure, the chromium content ranges from about 9% to about 19%.
% and the corresponding crack growth rate measurements show that the crack growth rate generally decreases with increasing chromium content. According to this graph, it appeared that it may be extremely difficult or impossible to devise an alloy composition that has a low chromium content and, at the same time, a low crack growth rate at a long residence time. .

However, the inventors have demonstrated that when the components of certain superalloy compositions are combined and properly alloyed, it is possible to form compositions that have both low chromium content and low crack growth rates at long residence times. I discovered something.

FIG. 3 shows an example of the relationship between the holding time when stress is applied to a test piece and the rate at which crack growth changes.

In this figure, the logarithm of the crack growth rate is plotted on the vertical axis and the residence time or holding time (seconds) is plotted on the horizontal axis. 5X1
A crack growth rate of 0' means that the cyclic stress factor is 25 k
The case of s i / i n may be seen as the ideal speed. If an ideal alloy is formed,
The alloy will exhibit this rate throughout the crack or hold time stressing the specimen. Such a phenomenon would be represented by straight line (a) in FIG. This straight line indicates that the crack growth rate is essentially independent of the holding or residence time while stressing the specimen.

In contrast, the curve (b
). It can be seen that for very short holding times, within a few seconds, the ideal line (a) and the practical curve (b) do not deviate too much.

When stressing the sample with such high frequency or short holding times, the crack growth rate is relatively low.

However, as the holding time to stress the sample increases, the experimental results for conventional alloys follow curve (b). Therefore, it can be seen that as the frequency of stress loading becomes lower and the holding time required for stress loading becomes longer, the deviation from the linear velocity increases. It is clear from FIG. 3 that by arbitrarily choosing a holding time of about 500 seconds, the crack growth rate can be increased by a factor of 100 from the standard rate of 5×10 to 5×10′.

Again, it would be desirable if the crack growth rate were independent of time, and this would ideally be represented by following curve (a) as the holding time increases and the frequency of stress application decreases. Probably.

Surprisingly, the inventors have discovered that by making small changes in the composition of the superalloy, it is possible to greatly improve the alloy's resistance to crack growth propagation at long residence times. In other words, it has been found that it is possible to reduce the rate of crack growth by modifying the alloying. Furthermore, it is also possible to increase the strength by processing the alloy. Such treatments are primarily heat treatments.

An alloy designated as Example HK79 was produced. The composition of this alloy was essentially as follows.

Component Concentration (wt%) Ni Balance C015 C' 10 Mo 3 Al 4 Ti 3.55 Ta 1.5O Nb 4 Re 0.OHf
0. OZr
0.06I C0.05 B 0.03Y
Oo 0° This alloy was subjected to various tests. The test results are plotted in Figures 4-10. Here, alloys designated with the letters "-8S" are alloys for which the data collected for that alloy was collected for "supersolvus" treated material. That is, the high temperature solid state heat treatment performed on this material was above the temperature at which the reinforcing γ' precipitates dissolve, but below the initial melting point. This usually results in a coarser grain size in the material. The reinforcing γ' phase precipitates again during subsequent cooling and aging.

Referring now to FIG. 4, crack propagation rate (inches/cycle) is plotted against cooling rate (77 minutes). Rene' 95- SS and HK7
The 9-SS sample had a holding time of 1 at the maximum stress factor.
000 seconds and tested in air at 12.00'F. Obviously, for samples cooled below 75 and below 350,
HK79-8S has a much lower crack growth rate than Rene' 95-8S. The dp/dN of samples cooled at rates above 1000 °C is somewhat lower than that of samples with Rene'> 95- SS cooled at the same rate. The range of cooling rates for parts
It should be noted that it is expected to range from 00°F/min to below 600°F/min.

As can be seen from the foregoing, the present invention provides an alloy having a unique combination of components both in terms of the types of components and their relative concentrations.

It is also clear that the alloy proposed by the present invention has novel and unique capabilities in terms of crack propagation inhibition. The low crack propagation rate d a /d N of the HK79-8S alloy, which is clear from FIG. 4, is a novel and remarkable result unique to the present invention. The first da/dN of about 1.2 x 10-4 found in a sample cooled at about 400" F/min.
When plotted in the figure, it is located at the lower right corner of the plot in Figure 1, and is below the 0.33 Hz line shown in the plot.

Similarly, with respect to Figure 2, the data points for the HK79-8S alloy of the present invention with 10% chromium and da/dN of 1.2X10' are well below the long residence time line and are well below the 0.33 Hz test. It is very close to, but below, the fatigue growth rate line for . The test data shown in Figure 4 is for a retention time of 1000 seconds, and the plot in Figure 2 is for a retention time of 900 seconds. Based on this, the data point for the alloy of the present invention is 0°33
It should be much closer to the 900 seconds line than it is to the Hz line, and it should even be above that line. However, in reality, exactly the opposite is observed. This is because small differences in composition can make dramatic differences to crack propagation rates in long cycle fatigue tests, and are particularly important in reducing such rates. This is quite surprising since the composition of the alloy differs only slightly from that found in the IN-100 alloy. As is clear from the graphs in the drawings accompanying this application, it is precisely this component and its proportions that result in the surprisingly unexpected and significant low fatigue crack propagation rates along with the highly desirable combination of strength and other properties. It is based on small differences in

Other properties of the alloy of the present invention will be explained below with reference to FIGS. 5-10.

The alloy of the present invention is similar to IN-100 in some respects, but in order to provide a basis for comparing the alloy of the present invention with alloys that are much stronger than IN-100, the alloy of the present invention and Rene ( A comparative test was conducted on samples of Rθne')95-SS. The tensile test results obtained at 750° F. are plotted in FIGS. 5 and 6, and the tensile test results obtained at 1400° F. are plotted in FIGS. 7 and 8.

First, reference is made to the test data plotted in FIG. Figure 5 shows the relationship between yield stress (ksl) and cooling rate ('F/min) for two alloy samples HK79-SS and Rene' 95-8S tested at 750''F. is plotted.

This plot clearly shows the superiority of the HK79-SS alloy sample when compared to the Rene' 95-SS sample over the range of cooling rates in which the part is expected to be used. ) 9
Both samples of 5-SS were all manufactured by powder metallurgy techniques and are therefore very similar to each other in terms of strength and other properties.

Figure 6 shows the alloy HK79 produced according to the above example.
-Rcne' as a SS sample and comparison
) 95-SS sample series, ultimate tensile strength (ksi) is plotted against cooling rate (F7 min). The samples tested were measured at 750°F. It is well known that Rene' 95 is one of the strongest known commercially available superalloys. As is clear from Fig. 6, the results of ultimate tensile strength measurements conducted on samples of HK79-SS alloy and Rcne' 95-SS alloy are as follows:
HK79-SS alloy is actually Rene'95-
It has been shown that it has higher tensile strength, especially ultimate tensile strength, than SS materials.

As can be seen from the plot in FIG.
From about 153 of the alloy sample cooled at F/min to 10
It ranges to yield stress of 165 or more for samples cooled at 000F/min or more.

Referring now to Figure 8, two alloy samples, both tested at 1400"F, namely Rene
') About 95-SS and HK79-SS 14.
The relationship between ultimate tensile strength at 00''F and cooling rate (77 minutes) is plotted.

The data plotted in FIGS. 5-8 also show, by comparison, that the alloys of the present invention have nearly identical tensile strength properties to those of Rcne' 95.

Referring now to Figure 9, this graph shows the H
The fracture life (hours) is plotted against the cooling rate (77 minutes) for the K79-SS and Rene' 95-8S samples.

As is clear from this graph, the fracture life of the HK79-3S sample is over 500 hours when the sample is cooled at approximately 75°F/min;
Cooling at a rate of 1/min or more increased the fracture life to about 800 hours. The fracture resistance of HK79-SS has been shown to be superior to Rene' 95-5S at all cooling rates tested.

A similar but not identical graph is shown in Figure 10. In FIG. 10, the equivalent temperature is plotted on the vertical axis for a sample with a stress rupture life of 100 hours. In other words, the plot in Figure 10 is gQksi in argon.

The sample tested at 1400"F shows the temperature it can withstand for 100 hours. Again, the difference in temperature for 100 hour stress rupture resistance based on cooling rate is evident from this graph.

Furthermore, with respect to the suppression of fatigue crack propagation, the alloys of the present invention have a cooling rate of 100°F/min to below 600°F/min, which would be used in the industrial production of Rene' 95, especially such alloys. Much superior to alloys manufactured in

What is remarkable about the achievement of the present invention is that lN-100
Compared with the composition of the alloy, the change in the composition of the HK79 alloy is relatively small, resulting in a significant improvement in fatigue crack propagation resistance.

The components of both IN-100 and HK79 are listed below to illustrate the small changes in alloy composition.

Table I Ingredients HK Ni 57°Co 15 Cr 10 Mo 3 79 1N-100 8160,55 5 0 AI 4 5.5T
i3. 55 4. 7Ta
1. 5 Nb 4 Zr 0.060,06 V 1 1C0.8
50,18 B 0.030,01 As is clear from Table 1 above, the only meaningful difference in the composition of alloy 1N-100 compared to the composition of alloy HK79 is that in the alloy of the present invention, aluminum is %, titanium is 1
615% by weight, 1.5% by weight of tantalum and 4
．． Only 0% by weight of niobium is added.

Such compositional changes can enhance or improve the basic strength properties of the alloy to those of Rene' 95, while at the same time providing fatigue crack suppression during long residence times for this alloy. That seems rather surprising. However, this is precisely the result of this compositional change, as evidenced by the data listed in the accompanying drawings and detailed above.

Other changes in the components that are not related to the above-mentioned significant changes in properties, particularly changes in the amount of added components, may be made. For example, small amounts of rhenium may be added without altering the unique and beneficial combination of properties found in the HK-79 alloy, particularly without detracting from such properties.

Although the alloys of the present invention have been described in terms of components and percentages of components that provide uniquely advantageous proportions with respect to crack propagation inhibition, other components, such as yttrium,
It will be appreciated that hafnium and the like can be included in the composition in percentages that do not interfere with the novel crack propagation control. For example, small amounts of yttrium, on the order of 0-0.1%, can be included in the alloys of the present invention without detracting from the unique and valuable combination of properties of the alloys.

[Brief Description of the Drawings] Figure 1 shows fatigue crack growth (in/cycle) plotted against ultimate tensile strength (ksi) on a logarithmic scale for fatigue crack propagation (ΔK at 30 ksi) at 650°C. It is a graph. FIG. 2 is a graph plotting the same test results as in FIG. 1, but the horizontal axis represents the chromium content (it amount %). FIG. 3 is a graph plotting the logarithm of the crack growth rate against the holding time (seconds) when stress is repeatedly applied to the test piece. FIG. 4 is a graph plotting the crack propagation rate da/dN (inch/cycle) against the cooling rate (bottom 7 minutes). Test conditions: 1200”F, in air, R-0.05
, 1000 seconds hold time, 25ksl J hill Δ is 0. Figure 5 is a graph of yield stress (ksi) at 750''F plotted against cooling rate (F7 min) on a logarithmic scale. Figure 6 is a graph of ultimate tensile strength (ksl) at 750''F plotted against cooling rate ('F/min) on a logarithmic scale. Figure 7 is a graph of yield stress (ksi) at 1400@F plotted against cooling rate (F/min). Figure 8 is a graph of yield stress (ksi) at 1400@F plotted against cooling rate (F7min). 1
400 is a graph of ultimate tensile strength (ksi) below 400. FIG. 9 is a graph plotting fracture life (hours) against cooling rate (F7 minutes) when a stress of 80 ksi is applied at 1400@F in argon. FIG. 10 is a graph plotting the temperature (in) at which a life of 100 hours can be expected at 80 ksi versus the cooling rate (F7 minutes).

Claims (6)

[Claims] (1) Alloy composition containing the following components in the following proportions: Ingredients Concentration in composition (wt%) Ni remainder Co12-18 Cr7~13 Mo2~4 Al3~5 Ti3.5~5.5 Ta1~2 Nb3~5 Re0.0~3.0 Hf0.0~0.75 Zr0.00~0.10 V0.0~2.0 C0.0~0.20 B0.01~0.10 W0.0~1.0 Y0.0-0.1. 2. The composition of claim 1, wherein the composition is cooled at a rate of no more than about 600°F/min. 3. The composition of claim 1, wherein the composition is cooled at a rate of 50 to 600 F/min. (4) Alloy composition containing the following components in the following proportions: Ingredients Concentration in composition (wt%) Ni remainder Co15 Cr10 Mo3 Al4 Ti3.55 Ta1.5 Nb4 Zr0.06 V1 C0.05 B0.03. 5. The composition of claim 4, wherein the composition is cooled at a rate of no more than about 600°F/min. 6. The composition of claim 4, wherein the composition is cooled at a rate of 50 to 600 degrees F per minute.