CH637994A5 - NICKEL BASED ALLOY. - Google Patents

Description

The present invention relates to nickel-based alloys, in particular alloys of the gamma prime type based on nickel containing platinum group metals.

In United Kingdom Patent No. 1,520,630, there are described and claimed certain nickel-based and cobalt-based alloys containing platinum group metals and essentially comprising (a) 40-78% Ni and / or Co, (b) traces at 25% Cr, (c) traces at 15% of metals of the platinum group and (d) traces at 13% Al and / or Ti. Such alloys have remarkable properties at high temperature, in particular with regard to their tensile and creep resistance, and are perfectly suited for applications such as the manufacture of elements used in the glass industry and in this field of glass. aeronautical industry relating to jet engines and gas turbine engines.

It is assumed that the metallurgical structure of the alloys described in this United Kingdom patent No. 1,520,630 comprises a matrix of gamma phase of nickel-chromium comprising a minimal proportion of metals of the platinum group, together with 65% by weight of gamma phase premium which is mainly constituted by NiîAl substituted by metals of the platinum group, chromium and other elements of the alloy. Most, that is to say probably more than 90%, of the platinum group metals are present in the gamma prime phase and, it is admitted that they mainly replace aluminum in this phase.

Although NÌ3 Al itself does not have useful physical properties for rigorous applications such as those described below, it is nevertheless generally accepted that it is the presence of NÌ3A1, that is to say the gamma prime phase, in particular such a phase also comprising platinum group metals, in association with one or more other phases, which gives this alloy its properties at high temperature. It is also admitted that the alloys comprising a gamma prime phase matrix have improved properties at high temperature compared with the alloys comprising a gamma phase matrix dispersed with a gamma prime phase precipitate, but hitherto such alloys have tended to have a relatively low corrosion resistance, in particular at high temperatures. It is therefore an object of the present invention to provide a new alloy which overcomes these disadvantages.

According to the invention, a nickel-based alloy is produced comprising, by weight except for impurities, aluminum (4-13.5%), chromium (trace at 6%), one or more platinum group metals (trace at 20% in total), the balance being nickel.

By “platinum group metals” is meant platinum, rhodium, iridium, ruthenium, palladium and osmium. Among these, it is particularly preferred to use one or more metals of the platinum group, rhodium and ruthenium.

According to one embodiment of the invention, an alloy is also produced containing hafnium (5% trace) and / or titanium (6% trace) and / or tantalum (12% trace).

According to another embodiment of the invention, an alloy is produced comprising, in addition, from traces to the specified weight, one or more of the following metals:

niobium 6%

carbon 0.15%

0.1% boron

cobalt 10%

molybdenum 14%

tungsten 14%

zirconium 1.75% scandium, yttrium or oxides thereof and / or rare earth metals or oxides 3%

0.25% silicon

magnesium 1%

iron 10%

manganese 0.25%

vanadium 2%

It should be understood that, in addition to the oxides of scandium, yttrium and the rare earth metals indicated above, other elements, for example Zr, alloys according to the invention may be present at least partially in the form of their oxides.

These oxides can be added either as they are to the other elements of the alloy or can be formed in situ under the conditions of manufacture of the alloy.

A particular alloy according to the invention can have the com5

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55

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637994

following position expressed in percent by weight: Al 7.3%, Ti 0.8%, Co 6.5%, Nb 0.99%, Mo 1.0%, Ta 10.5%, Cr 2%, W 2 %, C 0.05%, B 0.01%, Zr 0.07%, Pt 7.5% and the balance being nickel.

The alloys according to the invention can comprise a matrix of gamma prime dendritic phase filled with gamma and / or beta phase, alpha, borides, carbides etc., the precise structure depending on the aluminum content. It is assumed that the platinum group metal occurs at least in the gamma prime and NiAl beta phases. The alloys can be produced by the usual techniques of vacuum melting and casting, or by mechanical addition for example. A preferred method is directed solidification which increases the mechanical strength in the direction of solidification.

It has been found that the alloys according to the invention have properties at high temperature up to 1100 ° C. with regard to the tensile and oxidation resistance which are superior to those of most of the usual nickel superalloys and approximately comparable to the alloys known in the art comprising a gamma prime phase matrix. The alloys according to the invention also exhibit improved resistance to hot corrosion compared to most known superalloys and also alloys with a gamma prime matrix.

Table 1 below gives examples of the alloys according to the invention together with various alloys known in the art. The values for the composition are expressed in added weight and it should be understood that the analysis of any given alloy would probably give values originally different from those indicated.

Table 1

Composition of the alloy (% by weight)

Pt

Or

Al

Ti

Cr

Co w

Mo

Your

Nb

K

j

13.28

G

10.4

4.6

AT

16.6

9.2

4.1

B

16.2

6.8

4.0

R

8.73

8.69

4.28

H

9.7

3.4

3.7

S

8.7

8.05

3.2

3.45

J

7.1

3.2

3.4

7.8

8.1

2.0

W

7.96

5.74

2.94

3.2

7.2

7.52

1.95

GP4

6.8

3.9

2.6

6.52

8.1

4.1

GP5

15.2

4.8

3.7

2.7

7.5

7.9

4.1

L

7.2

3.2

7.8

3.2

6.0

X

8.08

5.82

2.98

3.23

7.32

2.97

5.62

NOT

7.1

3.1

3.4

7.7

5.6

1.7

3.2

Y

7.98

5.73

2.94

3.19

7.24

5.26

1.56

2.96

GP1

7.5

g

7.3

0.8

2

6.5

2

1.0

10.5

0.99

Ë

s <n

"EH

Ë

GP2A

u 0

7.3

1.0

2.5

7.5

2

1.5

7.0

2.5

Other

GP2B 7.0

GP3 4.6

GPY 7.5

6.9 0.9

10.0 1.2

7.05 0.8

2.2

2.5

2.0

7.5

7.2

7.0

1.8

2.0

2.0

1.5 6.0

1.3 5.5

1.0 10.0

2.2

2.2

1.0

C-0.05 B-0.01 Zr-0.07

C-0.08 B-0.02 Zr-0.05 Hf-1.5

C-0.08 B-0.02 Zr-0.05 Hf-1.5

C-0.08 B-0.02 Zr-0.05

C-0.05 B-0.01 Zr-0.07 Y-0.3

Table 2 and Figures 1 to 5 give the results for corrosion by salts in air. In each figure, the various alloys according to the invention by comparison with various 65 result of NÌ3AI (alloy K) is given for a purpose compa-alloys known in tests to establish their resistance to ratif.

637994

4

Table 2

Results of the test for measuring the resistance to corrosion by a coating of salt at 900 ° C. (1.5 mg / cm-2 of NaaSO ")

Alloys Duration of test in hours and weight gain in mg / cm2

24 hours 48 hours 72 hours 96 hours

K

5.1

mg / cm2

7.3

mg / cm2

10.5 mg / cm2

12.3

mg / cm2

G

32.3

mg / cm2

70.1

mg / cm2

104.6 mg / cm2

128.1

mg / cm2

AT.

4.9

mg / cm2

-

4.8. mg / cm2

5.4

mg / cm2

B

2.7

mg / cm2

3.2

mg / cm2

3.5 mg / cm2

3.8

mg / cm2

R

4.7

mg / cm2

11.2

mg / cm2

22.9 mg / cm2

41.5

mg / cm2

H

15.3

mg / cm2

24.5

mg / cm2

108 mg / cm2

111

mg / cm2

S

1.0

mg / cm2

3.7

mg / cm2

2.5 mg / cm2

5.0

mg / cm2

J

13

mg / cm2

23.5

mg / cm2

23.5 mg / cm2

23.9

mg / cm2

W

2.7

mg / cm2

4.3

mg / cm2

6.5 mg / cm2

7.8

mg / cm2

L

16.0

mg / cm2

28

mg / cm2

29.5 mg / cm2

30.3

mg / cm2

X

1.0

mg / cm2

2

mg / cm2

3.5 mg / cm2

-

mg / cm2

NOT

28.9

mg / cm2

75.9

mg / cm2

117.8 mg / cm2

123

mg / cm2

Y

1.0

mg / cm2

3.7

mg / cm2

4.1 mg / cm2

6.6

mg / cm2

The following table 3 and FIG. 6 show the results Table 3

for sulfurization resistance tests by immersion Sulphurization resistance test by total to total immersion at 925 ° C for alloys GP5 and GP4 and Figure 7 925 ° C in 10% NaCl and Na2So4.

shows the results of the alternating oxidation resistance test for alloys according to the invention and a superalloy 30:

commercially available. Duration of test in hours and weight loss per unit area

In alternate oxidation resistance tests, each (mg / cm)

cycle consists of heating the alloy to 1100 ° C and maintaining 1 hour 4 hours 15 hours

at this temperature for a total time of 40 minutes and then cool the alloy to 20 ° C and maintain it at this temperature 35 GP4 149.1 mg / cm2 430.7 mg / cm2 Fully etched for a total of 20 minutes . GP5 9.4 mg / cm2 40.1 mg / cm2 8.09 mg / cm2

In FIG. 7 the alloy M ARM is a commercially available alloy indicated for comparative purposes and consists of chromium 9%, cobalt 10%, tungsten 12%, niobium 1%, alu- Of course various modifications can be made.

5% minium, 2% titanium, 0.15% carbon, 0.015% boron, zirconia 40% skilled in the art with alloys which have just been 0.05% nium and the balance is nickel. described only by way of nonlimiting examples without departing from the scope of the invention.

B

4 sheets of drawings

Claims (6)

637994 1% iron 10% manganese 0.25% vanadium 1.75% scandium, yttrium or oxides thereof and / or rare earth metals or their oxides 1. A nickel-based alloy, characterized in that it comprises, expressed in percent by weight and with the exception of impurities, 2% 2. Alloy according to claim 1, characterized in that it comprises one or more metals as follows: - traces at 5% hafnium - traces of 6% titanium - traces at 12% tantalum. 2 3% silicon 0.25% magnesium 3. Alloy according to one of claims 1 or 2, characterized in that it contains, in addition, from traces to the indicated weight, one or more of the following metals: niobium 6% carbon 0.15% boron 0.1% cobalt 10% molybdenum 14% tungsten 14% zirconium 4. Alloy according to claim 3, characterized in that the scandium, yttrium and rare earth metals are at least partially present in the form of their respective oxides. - 4 to 13.5% aluminum - traces of 6% chromium - traces at 20% of one or more metals of the platinum group, the balance being nickel. 5. Alloy according to claim 3, characterized in that the metals niobium, carbon, boron, cobalt, molybdenum, tungsten, zirconium, silicon, magnesium, iron, manganese, vanadium are at least partially present in the form of their respective oxides. 6. Alloy according to claim 3, characterized in that it comprises: aluminum 7.3%, titanium 0.8%, cobalt 6.5%, niobium 0.99%, molybdenum 1.0%, tantalum 10.5 %, 2% chromium, 2% tungsten, 0.05% carbon, 0.01% boron, 0.07% zirconium, 7.5% platinum and the balance is nickel.