IT8224403A1 - NICKEL-BASED SUPER-ALLOY - Google Patents

Description

DOCUMENTATION

BOUND

SUPER-ALLOY NICKEL BASED

SUMMARY

Nickel-based superalloys containing Ni, Al, Mo and W have improved resistance to oxidation through the addition of quantities. coordinates of Cr, Ta and Y. The resulting alloys have resistance to oxidation and properties? high temperature mechanics that are superior to those of other super alloys.

TEXT OF THE DESCRIPTION

The present invention relates to the field of nickel-based superalloys which have both exceptional resistance to oxidation and exceptional properties. high temperature mechanics.

Previous researchers have worked with alloys based on the Ni-Al-Mo system. Is this work typified by U.S. Pat. N? 2,542,962 and 3,933,483.

U.S. Pat. N? 3.904.4G3 suggests adding 0, l-3? atomic (total) of one or more? elements selected from a group that includes Cr, Ta and W to the Ni-Al-Mo type of alloys.

According to the present invention, a class of nickel-based superalloys is endowed with a substantially increased resistance to oxidation through the addition of quantities. coordinates of Cr, Ta and Y. The improved oxidation behavior is obtained without noticeable detriment to the properties. mechanical.

The wide range of composition? 5.8-7.8% Al, 8-12% Mo, 4-8% W, 2-4% Cr,

1-2% Ta, 0-D, 3% Hf, 0.01-0.1% Y, the remainder being essentially nickel. A favorite range? 6.3-7.3% Al, 8.3-11.3% Mo, 5-7% W, 2.5-3.5% Cr, 1-2% Ta, 0.05-0.2% Hf, 0.01-0.07% Y.

Alloys within these ranges can be fabricated into useful articles using powder metallurgy techniques or can be cast to size and then heat treated.

Consequentially ? an object of the present invention is to provide nickel-based superalloys resistant to oxidation and with high mechanical strength.

The foregoing and other objects, features and advantages of the present invention will become more effective. clear from the following description of preferred embodiments and the accompanying drawings in which:

Fig. 1 illustrates the effect of varying the yttrium level on oxidation behavior.

Figs. 2A, 2B and 2C are scanning electron micrographs illustrating the oxide morphology obtained with various levels of yttrium.

L? Fig. 3 illustrates the effect of varying the chromium level on the oxidation behavior at 1093 ° C.

Fig. 4 illustrates the effect of varying the chromium level on the oxidation behavior at 1149 ° C.

Fig. 5 illustrates the stress fracture behavior of various alloys.

The present invention relates to a nickel-based superalloy having a specific and narrow composition range that provides an exceptional combination of oxidation resistance and properties. high temperature mechanics. The broad and preferred ranges of compositions are given in Tables 1 and 2. The tables are in percentages by weight as are all other percentages in this description unless otherwise specified. Table 1 also contains the equivalent values in atomic percentage. The particular combination of Ni-Al-Mo constituents? similar in some respects to that described in U.S. Pat. ND 2,542,962, 3,655,462, 3,094,403 and 3,933,483. Ni-Al-Mo alloys are known to have exceptional properties mechanical, however, so far their stability? surface and oxidation resistance had been unpredictable and marginal for long-term applications.

The core of the present invention lies in the addition of quantities. carefully coordinated Cr, Ta, Y and optionally Hf to these Ni-Al-Mo alloys to unpredictably improve oxidation resistance while simultaneously maintaining or even improving properties. mechanical.

Cr is added for oxidation resistance by promoting the formation of an Al ^ O ^ oxide rather than a NiO-based oxide. For this purpose at least about 2% Cr appears to be necessary. Increase the Cr level above about 4? it does not appear to provide substantial improvements compared to those obtained with about 3% Cr.

Since? the Cr concomitantly reduces the properties? mechanical, Cr additions higher than about 4? they are undesirable. Ta is added to stabilize the microstructure and Ta in the indicated levels overcomes the property deficit. mechanics resulting from the additions of Cr. What? the levels of Cr and Ta are correlated to a certain extent and an excellent alloy performance will come? obtained by coordinating the Ta and Cr levels in such a way that for high Cr levels, high levels are employed

Ta levels and for low Cr levels low Ta levels are employed

TABLE I

WIDE COMPOSITION

Low High

(SS by weight) (atom%) (? By weight) (atom%) Ni (remainder) (78.20) (78.65) (66.1) (66.15) Al 5.8 12.8 8 17.3

Mo 8.0 4.7 7.0

IAI 4.0 1.2 8.0 4

Cr 2.0 2.3 4.0 4.8

Ta 1.0 35 2.0 1.2

Y 0.01 0.01 0.1 0.03

Hf 0.0 0.0 0.0? 9

TABLE 2

PREFERRED COMPOSITION (? By weight)

Low High

1 remainder remainder

At 6.3 7.3

Mo 8.3 11.5

5,, 0 7.0

/

r 2.5 3.5

Ta 1Jn 2.0

Hf 0.0 0.2

0.01 0.7

At least one material chosen from the group consisting of Y and Hf must also be

added. These elements improve the adhesion of the surface oxide to the surfaces

alloys, in order to reduce flaking and minimize the weight loss due

to oxidation. It appears that from 0.1 to 0.3? by weight (total) of these elements reaTa and Cr so that for high levels of Cr, high levels are employed

Ta levels and for low Cr levels low Ta levels are employed.

TABLE I

WIDE COMPOSITION

_ Low High

(? by weight) (? atomic) (? by weight) (S *? atomic) Al 5,80000 12,54857 7,80000 17,31859

Mo 8.00000 4.86768 12.00000 7.49317

W? 4.00000 1.27007 8.00000 2.60682

Cr 2.00000 2.24539 4.00000 4.60865

Ta 1.00000 0.32261 2.00000 0.66216

Y 0.01000 0.00657 0.10000 0.06738

Hf 0.00000 0.00000 0.30000 0.10069

Ni 79.19002 78.73912 65.80003 67.14255 Total 100.00000 99.99998 100.00000 99.99997

TABLE 2

PREFERRED COMPOSITION (K by weight)

Low High

I rest no rest

At 6.3 7.3

Mo 8.3 11.5

W 5, 0 7.0

Cr 2, 5 3, 5

Ta 1, 0 2.0

Hf 0, 0 0, 2

Y 0, 01 0, 7

At least one material chosen from the group consisting of Y and Hf must also be

added. These elements improve the adhesion of the surface oxide to the surfaces

alloys, in order to reduce flaking and minimize the weight loss due

to oxidation. It appears that from 0.1 to 0.3 ?? in weight (total) of these elements will realize? the required function with the preferred range which? 0.02 to 0.2% (total) and V being preferably present in an amount? of at least 0.01-0.07%.

Figs. 1, 2 and 3 will help illustrate the effects of the previously reported elements. The figures list the alloy compositions tested and show the weight change during the oxidation test. Will you understand? that when an alloy oxidizes, it initially gains weight as a result of the formation of an oxide layer. Subsequently, if this oxide layer flakes off, it will result? weight loss and the oxide layer will reform. Flaking of the oxide and the resulting weight loss are undesirable since there? results in the emptying of the oxide-forming elements in the underlying substrate. The flaking of the oxide can? proceed to the point where he binds her? unable to reform the desired protective oxide layer in there? which forms a non-protective oxide layer. At this point the oxidation becomes more and more? rapid and uncontrolled and finally the sample will come? destroyed. Since? most alloys derive their resistance to oxidation from the formation of a protective oxide layer, the desirable weight change behavior? an initial slight increase in weight indicating the formation of a protective oxide layer followed by essentially no weight change (or a very slight increase).

The critical and unexpected result of the yttrium additions is illustrated in Fig. 1. This figure shows the weight loss suffered by different alloys with different levels of yttrium, after cyclic testing at 1204 ° C for 50 cycles of one hour. It is clear that for the base alloy tested (10% Mo, 6.7% Al, 6? W, 3% Or, 1.5515 Ta, 1% Hf, the rest Ni) the additions from about 0.01 to about 0.06% of Y produces a noticeable improvement in oxidation behavior. Bench? ? it was previously observed that Y pu? improve the oxidation performance of coatings (U.S. Patent Nos. 3,676,085 and 3,754,903) and of alloys (U.S. Pat.

N? 3,754,903) had never been shown to the extent that Y levels above about 0.1% are known to be harmful.

The results shown in Fig. 1 can be explained by reference to Figs. 2A, 2B and 20 which are SEM photographs (at 3000x magnification) of the oxidized surface of three samples. The composition of nominal sample? that shown in Fig. 2. Fig. 2A? of a sample containing 0.1% Hf and less than 0.002% Y. Fig. 2B? of a sample containing 0.1% Hf and 0.029% Y. Fig. 20? of a sample containing 0.1% Hf and 0.073% Y.

Figs. 2A and 2C both show coarse irregular oxide morphology and show evidence of oxide flaking while Fig. 2B shows evidence of adherent oxide morphology. What? Figs. 1? 2A, 2B and 2C clearly show that a quantity? limited criticism of Y produces a substantial improvement in oxidation behavior.

Figs. 3 and 4 illustrate that a critical chromium level? necessary for excellent resistance to oxidation. Fig. 3 shows the effect of varying the Cr content on the oxidation behavior of a base alloy containing 10% Mo, 7.4% Al, 6% W, 1.5% Ta, 0.1% Y and the rest Ni. Can you? see that under the test conditions (500 cycles of one hour of oxidation in the oven at 1093 ° C) the desired minimum weight variation is obtained with a Cr level of about 3%.

Fig. 4 reaches the same point using cyclic oxidation data generated at 1149 <D> C. The Figure shows the change in weight as a function of time in the test. Four curves are plotted for a containing base alloy

10% Mo, 6.6% Al, 1.5% Ta, 0.1% Y and the rest Ni (with variable Cr levels).

The effect of increasing Cr? to rotate the curves upwards towards the horizontal (or zero weight variation).

Figs. 3 and 4 illustrate that a Cr level of about 3? I? necessary to provide good oxidation behavior in this class of alloys.

The properties Mechanics of Al-Mo alloys have been shown in the previous literature to be superior in many respects to those of conventional superalloys. The present invention with the balanced additions of Cr, Ta, Y and / or Hf achieves a substantially improved oxidation behavior in combination with properties. mechanical that are at least equivalent and in some cases superior to the properties? base line Al-Mo-Ni alloys. There? ? a sharp contrast compared to typical alloys in which the improvement of a property? it is invariably accompanied by a decrease in other properties.

Fig. 5? a stress failure pattern for several alloys including the conventional MAR-M200 superalloy described above and an alloy that falls within the scope of the present invention. The data in Fig. 5 are for the properties? of rupture under stress of the various compositions tested in the form of single crystal in the orientation <111 ^. How can you? see figure, the modified Ni-Al-Mo composition has an improved stress rupture life when compared to the other alloys tested. The modified alloy appears to have a temperature improvement of approximately 1D3 ?C when compared to conventional superalloys. There? means that under equivalent stress conditions, the alloy of the present invention could be operated at temperatures of 105 ° C plus? high and still achieve the same life span of the parts. This elevated temperature could be the result of a higher engine operating temperature or reduced cooling air flow if the engine temperature remained the same.

Both of these alternatives give improved economics. Another possibility? ? that of maintaining operating conditions including temperature at the same level and obtaining substantially increased part life. Finally, the same temperature could be maintained, but by increasing the operational stress, you can achieve improved performance for the same fuel consumption and life of the parts.

The compositions described above can be used in the form of cast single crystal or alternatively they can be fabricated in parts using powder metallurgical techniques followed by directional recrystallization to obtain an aligned grain structure which in the limiting case can be produced. be a single crystal.

In case you choose the cast single crystal route,? It is necessary for the cast part to be homogenized and heat treated as discussed in U.S. Pat. N? 177.047 Series. If the part is to be manufactured through the powder metallurgical system, the composition can be manufactured. be formed into powder using different techniques bench? a technique resulting in a rapid solidification regime is desirable because of the homogeneity? improved as a result. Such a process is described in U.S. Pat. N? 4,025,249, 4,053,264 and 4,078,873. The resulting powder is then consolidated and directionally recrystallized to produce the desired structure. Directional recrystallization is described in U.S. Pat. N? No. 3,975,219 and specific systems for obtaining different crystallographic alignments in the final structure are described in the patent application filed on the same date by the same applicant entitled "Method for the production of superalloy material in

Claims (21)

1. Nickel-based superalloy with high mechanical strength and oxidation resistance, essentially consisting of: 5, 8 - 7.88 Al, 8 - 128 Mo, 4 - 88 W, Z - 48 Cr, 1 - 28 Ta, 0 - 0.38 Hf, 0.01 - 0.18 Y, the rest Ni. 2. Nickel-based superalloy resistant to oxidation and high mechanical strength consisting essentially of: 6.3 - 7.38 Al, 8.5 - 11.58 Mo, 3 - 78 W, 2.5 - 3.58 Cr, 1 - 28 Ta, 0 - 0.28 Hf 0.01 - 0.078 Y, the rest Ni. ANNEX A 'Amendments to the description of the patent application N? 24403 A / 82 contained in N? 1 apostille, requests with request filed on 21 JULY 1986 Footnote 1 4 - Table I Replace the original Table I with the following: TABLE I WIDE COMPOSITION _ Low High (? by weight) (atom%) (? by weight) (atomic K) Al 5.80000 12.54857 7.80000 17.31859 Mo 8.00000 4.86768 12.00000 7, 49317 W 4.00000 1.27007 8 .00000 2, 60682 Cr 2.00000 2.24539 4.00000 4, 60865 Ta 1.00000 0.32261 2.00000 0.66216 Y 0.01000 0.00657 0.10000 0, 06738 Hf 0.00000 0.00000 0.30000 0, 10069 Ni 79.19002 78.73912 65.80003 67, 14255 Total 100.00000 100.00000 99, 99997 Ta and Or so that for high levels of Cr, high levels are used Ta levels and for low Cr levels are low Ta Postill levels used? -1 - see Annex A? - a- TABLE I WIDE COMPOSITION Low High (? in so) (?? atomic) in pe so) ('D atomic ^ i (remainder 20) (7B 65 66 (66.15) Al 5.8 12 17.3 Mo 8.0 12.0 7.0 4.0 1, 8, 0 2.4 Cr 2.0 4, 0 4.8 to 1, Q 35 2.0 2 01 01 0.05 Hf "0.3 21 JUL.1986 TABLE 2 OFFICES VETTI RICCAR LO. s.R.i PREFERRED COMPOSITION (% by weight) Low High I rest no rest At 6.3 7.3 I 8.3 11.5 W 5.0 7.0 Cr 2.5 3.5 Ta 1.0 2.0 Hf 0.0 0.2 V 0.01 0.7 At least one material chosen from the group consisting of Y and Hf must also be added. These elements improve the adhesion of the surface oxide to the surfaces alloys, in order to reduce flaking and minimize the weight loss due to oxidation. It appears that from 0.1 to 0.3 ?? by weight (total) of these elements rea DESCRIPTION Field of technique The present invention relates to the field of nickel-based superalloys which have both exceptional resistance to oxidation and exceptional properties. high temperature mechanics. Foundation of the technique Previous researchers have worked with alloys based on the Ni-Al-Mo system. Is this work typified by U.5.A N? 2,542,962 and 3,933,483. U.5.A. N <D> 3,904,403 suggests adding 0, l-3? atomic (total) of one or more? elements selected from a group that includes Cr, Ta and W to the Ni-Al-Mo type of alloys. According to the present invention, a class of nickel-based superalloys is endowed with a substantially increased resistance to oxidation through the addition of quantities. coordinates of Cr, Ta and Y. The improved oxidation behavior is obtained without noticeable detriment to the properties. mechanical. The wide range of composition? 5.8-7.8% Al, 8? 12 ?? Mo, A-8% W, 2-A% Cr, 1-2% Ta, 0-0.3% Hf, 0.01-0.1% Y, the remainder being essentially nickel. A favorite range? 6.3-7.3% Al, 8.5-11.5% Mo, 5-7% W, 2.5-3.5% Or, 1-2% Ta, 0.05-0.2% HF, 0.01-0.07% Y. Alloys within these ranges can be fabricated into useful articles using powder metallurgy techniques or can be cast to size and then heat treated. Consequentially ? an object of the present invention is to provide nickel-based superalloys resistant to oxidation and with high mechanical strength. The foregoing and other objects, features and advantages of the present invention will become more effective. clear from the following description of preferred embodiments and the accompanying drawings in which: Fig. 1 illustrates the effect of varying the yttrium level on oxidation behavior. Figs. 2A, 2B and 2C are scanning electron micrographs illustrating the oxide morphology obtained with various levels of yttrium. Fig. 3 illustrates the effect of varying the chromium level on the oxidation behavior at 1093 ° C. Fig. A illustrates the effect of varying the chromium level on the oxidation behavior at 11A9? C. Fig. 5 illustrates the stress fracture behavior of various alloys. The present invention relates to a nickel-based superalloy having a narrow and specific composition range that provides an exceptional combination of oxidation resistance and properties. high temperature mechanics. The broad and preferred ranges of composition are shown in Tables 1 and 2. The tables are in percentages by weight as are all other percentages in this description unless otherwise specified. Table 1 also contains the equivalent values in atomic percentage. The particular combination of constituents Ni-Al-Flo? similar in some respects to that disclosed in U.S. Pat. N? 2,542,962, 3,655,462, 3,094,403 and 3,933,483. Ni-Al-Mo alloys are known to have exceptional properties. mechanical, however, so far their stability? surface and oxidation resistance had been unpredictable and marginal for long-term applications. The core of the present invention lies in the addition of quantities. carefully coordinated Cr, Ta, Y and optionally Hf to these Ni-Al-Mo alloys to unpredictably improve oxidation resistance while simultaneously maintaining or even improving properties. mechanical. Cr is added for oxidation resistance by promoting the formation of an Al ^ O ^ oxide rather than a NiO-based oxide. For this purpose at least about 2% Cr appears to be necessary. Increasing the Cr level above about 4% does not appear to provide substantial improvements over those obtained with about 3% Cr. Since? the Cr concomitantly reduces the properties? mechanical, Cr additions above about 4% are undesirable. Ta is added to stabilize the microstructure and Ta in the indicated levels overcomes the property deficit. mechanics resulting from the additions of Cr. What? the levels of Cr and Ta are to a certain extent correlated and an excellent alloy performance will come? obtained by coordinating the Ta and Cr levels in such a way that for high Cr levels, high levels are employed Ta levels and for low Cr levels low Ta levels are employed. TABLE I WIDE COMPOSITION Low High (? by weight) (? atomic) (?? by weight) (? atomic) Ni (remainder) (78.20) (78.65) (66.1) (66.15) Al 5.8 12.8 7.8 17.3 Mo 8.0 4.7 12.0 7.0 W 4.0 1.2 8.0 2.4 Cr 2.0 2.3 4.0 4.8 Ta 1.0 0.35 2.0 1.2 Y 0.01 0.01 0.1 0.05 Hf 0.0 0.0 0.0 0.3 TABLE 2 PREFERRED COMPOSITION (? I by weight) Low High I rest no rest At 6.3 7.3 Mo 8.3 11.5 W 5.0 7.0 Or 2.5 3.5 Ta 1.0 2.0 Hf 0.0 0.2 Y 0.01 0.7 At least one material chosen from the group consisting of Y and Hf must also be added. These elements improve the adhesion of the surface oxide to the surfaces alloys, in order to reduce flaking and minimize the weight loss due to oxidation. It appears that from 0.1 to 0.3 ?? in weight (total) of these elements will realize? the required function with the preferred range which? 0.02 to 0.2? (total) and Y being preferably present in an amount? of at least 0.01-0.07 ?. Figs, 1, 2 and 3 will help illustrate the effects of the previously reported elements. The figures list the alloy compositions tested and show the weight change during the oxidation test. Will you understand? that when an alloy oxidizes, it initially gains weight as a result of the formation of an oxide layer. Subsequently, if this oxide layer flakes off, it will result? weight loss and the oxide layer will reform. Flaking of the oxide and the resulting weight loss are undesirable since there? results in the emptying of the oxide-forming elements in the underlying substrate. The flaking of the oxide can? proceed to the point where he binds her? unable to reform the desired protective oxide layer in there? which forms a non-protective oxide layer. At this point the oxidation becomes more and more? rapid and uncontrolled and finally the sample will come? destroyed. Since? most alloys derive their resistance to oxidation from the formation of a protective oxide layer, the desirable weight change behavior? an initial slight increase in weight indicating the formation of a protective oxide layer followed by essentially no weight change (or a very slight increase). The critical and unexpected result of the yttrium additions is illustrated in Fig. 1. This figure shows the weight loss suffered by different alloys with different levels of yttrium, after cyclic testing at 12D4? C for 3Q one-hour cycles. F <1> it is clear that for the base alloy tested (10? Ma, 6,7 ?? Al, 6? W, 3 ?? Cr, i, 5? Ta, 1% Hf, the remainder Ni) the additions from about 0.01 to about 0.06 ?? of Y produce a notable improvement in oxidation behavior. Bench? ? it was previously observed that Y pu? improve the oxidation performance of coatings (U.S. Patent Nos. 3,676,085 and 3,754,903) and of alloys (U.S. Patent No. N <D> 3,754,903) had never been shown to the extent that Y levels above about 0.1% are known to be harmful. The results shown in Fig. 1 can be explained by reference to Figs. 2A, 2B and 2C which are SEM photographs (at 3000x magnification) of the oxidized surface of three samples. The composition of nominal sample? that shown in Fig. 2. Fig. 2A? of a sample containing 0.1% Hf and less than 0.002% Y. Fig. 2B? of a sample containing 0.1% Hf and 0.029% Y. Fig. 2C? of a sample containing 0.1% Hf and 0.073% Y. < Figs. 2A and 2C both show coarse irregular oxide morphology and show evidence of oxide flaking while Fig. 2B shows evidence of adherent oxide morphology. What? Figs. 1? 2A, 2B and 2C clearly show that a quantity? limited criticism of Y produces a substantial improvement in oxidation behavior. Figs. 3 and 4 illustrate that a critical chromium level? necessary for excellent resistance to oxidation. Fig. 3 shows the effect of varying the Cr content on the oxidation behavior of a base alloy containing 10% Mo, 7.4% Al, 6% W, 1.5% Ta, 0.1% Y and the rest Ni. Can you? see that under the test conditions (500 cycles of one hour of oxidation in the oven at 1093 ° C) the desired minimum weight variation is obtained with a Cr level of about 3%. Fig. 4 reaches the same point using cyclic oxidation data generated at 1149 ° C. The Figure shows the change in weight as a function of time in the test. Four curves are plotted for a containing base alloy 1G% Mo, 6.6% Al, 1.5% Ta, 0.1% Y and the rest Ni (with variable Cr levels). The effect of increasing Cr? that of rotating the curves upwards towards the horizontal (or zero weight variation). Figs. 3 and 4 illustrate that a Cr level of about 3? ? necessary to provide good oxidation behavior in this class of alloys. The properties Mechanics of Al-Mo alloys have been shown in the previous literature to be superior in many respects to those of conventional superalloys. The present invention with the balanced additions of Cr, Ta, Y and / or Hf achieves a substantially improved oxidation behavior in combination with properties. mechanical that are at least equivalent and in some cases superior to the properties? base line Al-Mo-Ni alloys. There? ? a stark contrast to typical alloys where the improvement of a property? it is invariably accompanied by a decrease in other properties. Fig. 5? a stress failure pattern for various alloys including the conventional superalloy MAR-M2D0 previously described and an alloy which falls within the scope of the present invention. The data in Fig. 5 are for the properties? of rupture under stress of the various compositions tested in the form of single crystal in the orientation <111 ^. How can you? see figure, the modified Ni-Al-Mo composition has an improved stress rupture life when compared to the other alloys tested. The modified alloy appears to have a temperature improvement of approximately 105 ° C when compared to conventional superalloys. There? means that under the equivalent stress conditions, the alloy of the present invention could be operated at temperatures of 1 D5 ° C µl. high and still achieve the same life span of the parts. This elevated temperature could be the result of a higher engine operating temperature or reduced cooling air flow if the engine temperature remained the same. Both of these alternatives give improved economics. Another possibility? ? that of maintaining operating conditions including temperature at the same level and obtaining substantially increased part life. Ultimately, the same temperature could be maintained, but by increasing the operational stress, you can achieve improved performance for the same fuel consumption and parts life. The compositions described above can be used in the form of cast single crystal or alternatively they can be fabricated in parts using powder metallurgical techniques followed by directional recrystallization to obtain an aligned grain structure which in the limiting case can be produced. be a single crystal. In case you choose the cast single crystal route,? It is necessary for the cast part to be homogenized and heat treated as discussed in U.S. Pat. N <D> Series 177.047. If the part is to be manufactured through the powder metallurgical system, the composition can be manufactured. be formed into powder using different techniques bench? a technique resulting in a rapid solidification regime is desirable because of the homogeneity? improved as a result. Such a process is described in U.S. Pat. N? 4,025,249, 4,053,264 and 4,078,873. The resulting powder is then consolidated and directionally recrystallized to produce the desired structure. Directional recrystallization is described in U.S. Pat. N? No. 3,975,219 and specific systems for obtaining different crystallographic alignments in the final structure are described in the patent application filed on the same date by the same applicant entitled "Method for the production of superalloy material in 1. Nickel-based superalloy with high mechanical strength and oxidation resistance, essentially consisting of: 5, 8 - 7.8% Al, 8 - 12% Mo, 4 - 8% W, 2 - 4% Cr, 1 - 2% Ta, 0 - 0.3% Hf, 0.01 - 0.1% Y, the rest Ni. 2. Nickel-based superalloy resistant to oxidation and high mechanical resistance essentially consisting of: 6.3 - 7.3% Al, 8.5 - 11.5% Mo, 5 - 7% W, 2.5 - 3.5% Cr, 1 - 2% Ta, 0 - 0.2% Hf 0.01 - 0.07% Y, the rest Ni.