Fabricable, high strength, oxidation resistant Ni—Cr—Co—Mo—Al alloys
Ni—Cr—Co—Mo—Al based alloys are disclosed which contain 15 to 20 wt. % chromium, 9.5 to 20 wt. % cobalt, 7.25 to 10 wt. % molybdenum, 2.72 to 3.89 wt. % aluminum, certain minor elemental additions, along with typical impurities, a tolerance for up to 10.5 wt. % iron, and a balance of nickel. These alloys are readily fabricable, have high creep strength, good thermal stability, and excellent oxidation resistance up to as high as 2100° F. (1149° C.). This combination of properties is useful for a variety of gas turbine engine components, including, for example, combustors.
1. A nickel-chromium-cobalt-molybdenum-aluminum based alloy that when in annealed sheet form has an average metal affected value of not more than 3 mils/side when subjected to oxidation testing in flowing air at 2100° F. for 1008 hours, has a creep-rupture life of at least 325 hours when tested at 1800° F. under a load of 2.5 ksi, has ductility of greater than 10% when tested using a room temperature tensile test following a thermal exposure at 1400° F. for 100 hours, and has a modified CHRT test ductility greater than 7% when tested at 1450° F., the alloy having a composition comprised in weight percent of:
15 to 20
chromium
9.5 to 20
cobalt
7.25 to 10
molybdenum
2.72 to 3.89
aluminum
up to 10.5
iron
0.02 to 0.75
titanium
present up to 0.15
carbon
present up to 0.6
silicon
up to 0.015
boron
up to 0.2
niobium
up to 0.5
tungsten
up to 1.5
tantalum
up to 1
hafnium
up to 1
manganese
up to 0.06
zirconium
with a balance of nickel and impurities, the alloy further satisfying the following compositional relationship defined with elemental quantities being in terms of weight percent:
Al+0.56Ti+0.29Nb+0.15Ta≤3.9.
2. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 1 , containing titanium, from 0.2 to 0.75 wt. %.
3. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 1 , containing tantalum, from 0.2 to 1.5 wt. %.
4. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 1 , containing hafnium, from 0.2 to 1 wt. %.
5. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 1 , containing both of the elements hafnium and tantalum where the sum of the two elements is between 0.2 and 1.5 wt. %.
6. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 1 , containing traces of at least one of magnesium, calcium, and any rare earth elements up to 0.05 wt. %.
7. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 1 , containing at least one of the following impurities: copper up to 0.5 wt. %, sulfur up to 0.015 wt. %, and phosphorous up to 0.03 wt. %.
8. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 1 wherein the alloy contains in weight percent:
16 to 20
chromium
15 to 20
cobalt
7.25 to 9.75
molybdenum
2.9 to 3.7
aluminum
up to 5
iron
0.2 to 0.75
titanium
present up to 0.12
carbon
present up to 0.5
silicon
up to 0.008
boron
0.2 to 1.5
tantalum
up to 0.04
zirconium.
9. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 1 , wherein the alloy contains in weight percent:
18 to 20
chromium
18 to 20
cobalt
7.25 to 8.25
molybdenum
>3 to 3.5
aluminum
up to 2
iron
0.2 to 0.6
titanium
0.02 to 0.12
carbon
0.05 to 0.4
silicon
present up to 0.005
boron
0.2 to 1
tantalum
up to 0.5
hafnium
up to 0.5
manganese
present up to 0.04
zirconium.
10. A nickel-chromium-cobalt-molybdenum-aluminum based alloy that when in annealed sheet form has an average metal affected value of not more than 3 mils/side when subjected to oxidation testing in flowing air at 2100° F. for 1008 hours, has a creep-rupture life of at least 325 hours when tested at 1800° F. under a load of 2.5 ksi, has ductility of greater than 10% when tested using a room temperature tensile test following a thermal exposure at 1400° F. for 100 hours, and has a modified CHRT test ductility greater than 7% when tested at 1450° F., the alloy having a composition comprised in weight percent of:
15 to 20
chromium
9.5 to 20
cobalt
7.25 to 10
molybdenum
2.72 to 3.89
aluminum
up to 5
iron
0.02 to 0.75
titanium
present up to 0.15
carbon
present up to 0.6
silicon
up to 0.015
boron
up to 1
niobium
up to 1.5
tantalum
up to 1
hafnium
up to 2
tungsten
up to 1
manganese
up to 0.06
zirconium
with a balance of nickel and impurities, the alloy further satisfying the following compositional relationship defined with elemental quantities being in terms of weight percent:
Al+0.56Ti+0.29Nb+0.15Ta≤3.9.
11. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 , containing titanium, from 0.2 to 0.75 wt. %.
12. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 , containing tantalum, from 0.2 to 1.5 wt. %.
13. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 , containing hafnium, from 0.2 to 1 wt. %.
14. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 , containing niobium, from 0.2 to 1 wt. %.
15. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 , containing at least two of hafnium, tantalum, and niobium, where the sum of these elements is between 0.2 wt. % and 1.5 wt. %.
16. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 , containing traces of at least one of magnesium, calcium, and any rare earth elements up to 0.05 wt. %.
17. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 , containing at least one of: copper up to 0.5 wt. %, sulfur up to 0.015 wt. %, and phosphorous up to 0.03 wt. %.
18. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 wherein the alloy contains in weight percent:
16 to 20
chromium
15 to 20
cobalt
7.25 to 9.75
molybdenum
2.9 to 3.7
aluminum
0.2 to 0.75
titanium
present up to 0.12
carbon
present up to 0.5
silicon
up to 0.008
boron
0.2 to 1.5
tantalum
up to 0.04
zirconium.
19. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 10 , wherein the alloy contains in weight percent:
18 to 20
chromium
18 to 20
cobalt
7.25 to 8.25
molybdenum
>3 to 3.5
aluminum
up to 2
iron
0.2 to 0.6
titanium
0.02 to 0.12
carbon
0.05 to 0.4
silicon
present up to 0.005
boron
0.2 to 1
tantalum
up to 0.5
hafnium
up to 0.5
tungsten
up to 0.5
manganese
present up to 0.04
zirconium.
20. A nickel-chromium-cobalt-molybdenum-aluminum based alloy that when in annealed sheet form has an average metal affected value of not more than 3 mils/side when subjected to oxidation testing in flowing air at 2100° F. for 1008 hours, has a creep-rupture life of at least 325 hours when tested at 1800° F. under a load of 2.5 ksi, has ductility of greater than 10% when tested using a room temperature tensile test following a thermal exposure at 1400° F. for 100 hours, and has a modified CHRT test ductility greater than 7% when tested at 1450° F., the alloy having a composition comprised in weight percent of:
15.3 to 19.9
chromium
9.7 to 20.0
cobalt
7.5 to 10.0
molybdenum
2.72 to 3.78
aluminum
up to 10.4
iron
0.02 to 0.49
titanium
0.085 to 0.120
carbon
0.002 to 0.005
boron
up to 0.2
niobium
up to 0.5
tungsten
0.13 to 0.49
silicon
up to 1.0
tantalum
up to 0.48
hafnium
up to 0.5
manganese
up to 0.02
yttrium
0.01 to 0.04
zirconium
with a balance of nickel and impurities, the alloy further satisfying the following compositional relationship defined with elemental quantities being in terms of weight percent:
Al+0.56Ti+0.29Nb+0.15Ta≤3.89.
21. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 20 , containing traces of at least one of magnesium, calcium, and any rare earth elements up to 0.05 wt. %.
22. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 20 , containing one or more of the following as impurities: niobium up to 0.2 wt. %, tungsten up to 0.5 wt. %, copper up to 0.5 wt. %, sulfur up to 0.015 wt. %, and phosphorous up to 0.03 wt. %.
23. A nickel-chromium-cobalt-molybdenum-aluminum based alloy that when in annealed sheet form has an average metal affected value of not more than 3 mils/side when subjected to oxidation testing in flowing air at 2100° F. for 1008 hours, has a creep-rupture life of at least 325 hours when tested at 1800° F. under a load of 2.5 ksi, has ductility of greater than 10% when tested using a room temperature tensile test following a thermal exposure at 1400° F. for 100 hours, and has a modified CHRT test ductility greater than 7% when tested at 1450° F., the alloy having a composition comprised in weight percent of:
15.3 to 19.9
chromium
9.7 to 20.0
cobalt
7.5 to 10.0
molybdenum
2.72 to 3.78
aluminum
up to 4.5
iron
0.02 to 0.49
titanium
0.085 to 0.120
carbon
0.002 to 0.005
boron
up to 1.0
niobium
up to 1.94
tungsten
0.13 to 0.49
silicon
up to 1.0
tantalum
up to 0.48
hafnium
up to 0.5
manganese
up to 0.02
yttrium
0.01 to 0.04
zirconium.
with a balance of nickel and impurities, the alloy further satisfying the following compositional relationship defined with elemental quantities being in terms of weight percent:
Al+0.56Ti+0.29Nb+0.15Ta≤3.89.
24. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 23 , containing traces of at least one of magnesium, calcium, and any rare earth elements up to 0.05 wt. %.
25. The nickel-chromium-cobalt-molybdenum-aluminum based alloy of claim 23 , containing one or more of the following as impurities: niobium up to 0.2 wt. %, tungsten up to 0.5 wt. %, copper up to 0.5 wt. %, sulfur up to 0.015 wt. %, and phosphorous up to 0.03 wt. %.