Hybrid turbine blade for improved engine performance or architecture

• US 10,035,185 B2
• Filed: 12/13/2013
• Issued: 07/31/2018
• Est. Priority Date: 12/14/2012
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Shah, Dilip M., Cetel, Alan D.
• Primary Examiner(s): Klemanski, Helene
• Application Number:
  US14/651,911
• Publication Number:
  US 20150321249A1
• Time in Patent Office: 1,691 Days
• Field of Search: 420445, 420443
• CPC Class Codes: B22D 19/16 for making compound objects cast of two or more different metals, e.g. for making rolls for rolling mills casting compound ingots B22D7/02
• CPC Class Codes: B22D 21/025 Casting heavy metals with high melting point, i.e. 1000 - 1600 degrees C, e.g. Co 1490 degrees C, Ni 1450 degrees C, Mn 1240 degrees C, Cu 1083 degrees C
• CPC Class Codes: B22D 21/06 Casting non-ferrous metals with a high melting point, e.g. metallic carbides B22D21/02 takes precedence
• CPC Class Codes: B22D 25/02 by its peculiarity of shape; of works of art cylinders, pistons B22D15/02
• CPC Class Codes: B22D 27/045 Directionally solidified castings
• CPC Class Codes: C22C 19/057 with the maximum Cr content being less 10%
• CPC Class Codes: F01D 5/14 Form or construction selecting particular materials, measures against erosion or corrosion F01D5/28
• CPC Class Codes: F01D 5/147 Construction, i.e. structural features, e.g. of weight-saving hollow blades F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18
• CPC Class Codes: F01D 5/28 Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
• CPC Class Codes: F05D 2220/30 in turbines
• CPC Class Codes: F05D 2230/21 by casting
• CPC Class Codes: F05D 2230/211 by precision casting, e.g. microfusing or investment casting
• CPC Class Codes: F05D 2300/131 Molybdenum
• CPC Class Codes: F05D 2300/132 Chromium
• CPC Class Codes: F05D 2300/133 Titanium
• CPC Class Codes: F05D 2300/135 Hafnium
• CPC Class Codes: F05D 2300/17 Alloys
• CPC Class Codes: F05D 2300/606 Directionally-solidified crystalline structures
• CPC Class Codes: F05D 2300/609 Grain size

Abstract

A method is provided for casting an article such as a blade having an attachment root and an airfoil, the airfoil having a proximal end and a distal end. The method comprises introducing a molten alloy into a mold; and varying a composition of the introduced alloy during the introduction so as to produce a compositional variation.

Claims

1. An alloy comprising, by weight percent:

nickel as a largest content;

4.5-8.5 Cr;

0.5-1.5 Mo;

2.5-3.5 W;

1.5-2.5 Ta;

5.5-7.5 Al;

4.5-5.5 Co;

0-4 Re; and

0.05-0.20 Hf.

2. The alloy of claim 1 comprising, by weight percent:

5-8 said Cr; and

0.5-1.0 said Mo.

3. The alloy of claim 1 consisting essentially of by weight percent:

nickel as a largest content;

4.5-8.5 Cr;

0.5-1.5 Mo;

2.5-3.5 W;

1.5-2.5 Ta;

5.5-7.5 Al;

4.5-5.5 Co;

0-4 Re; and

0.05-0.20 Hf.

4. The alloy of claim 1 further comprising no more than trace amounts of other elements, if any.

5. The alloy of claim 1 forming a first portion of a blade airfoil, with a denser and less oxidation resistant alloy along a second portion of the airfoil inboard of the first portion.

6. The alloy of claim 1 forming a first portion of a blade airfoil, with an at least 5% denser alloy along a second portion of the airfoil inboard of the first portion.

7. The alloy of claim 5 wherein:

the blade has a shroud at a distal end of the airfoil; and

the shroud is along the first portion.

8. The alloy of claim 5 wherein:

the blade has a density variation of 6-10%.

9. The alloy of claim 1 comprising, by weight percent:

said nickel as a largest content;

7.5-8.5 Cr;

0.5-1.5 Mo;

2.5-3.5 W;

1.5-2.5 Ta;

6.0-7.0 Al;

4.5-5.5 Co;

0-4.0 Re; and

0.05-0.20 Hf.

10. The alloy of claim 1 comprising, by weight percent:

said nickel as a largest content;

4.7-8.3 Cr;

0.7-1.3 Mo;

2.7-3.3 W;

1.7-2.3 Ta;

5.7-7.0 Al;

4.7-5.3 Co;

0-3.5 Re; and

0.05-0.20 Hf.

11. The alloy of claim 1 comprising, by weight percent:

said nickel as a largest content;

4.5-8.5 Cr;

0.5-1.5 Mo;

2.5-3.5 W;

1.5-2.5 Ta;

5.5-7.0 Al;

4.5-5.5 Co;

0-4.0 Re; and

0.05-0.20 Hf.

13. A method of casting a blade, the blade having an attachment root and an airfoil, the airfoil having a proximal end and a distal end, the method comprising:

introducing a molten alloy into a mold; and

varying a composition of the introduced alloy during the introduction so as to produce a compositional variation, the compositional variation providing the alloy of claim 1 along a portion of the blade.

14. The method of claim 13 wherein:

the compositional variation includes variation along the airfoil.

15. The method of claim 13 wherein:

the compositional variation provides said portion as an outboard portion of the blade with a lower density than an inboard portion of the blade.

16. The method of claim 13 wherein:

the compositional variation provides said portion as an outboard portion of the airfoil with a lower density than an inboard portion of the airfoil.

17. The method of claim 13 wherein:

the compositional variation provides three compositional zones with transitions between adjacent zones.

18. The method of claim 17 wherein:

the three compositional zones comprise a first zone at least partially along the attachment root, a second zone at least partially along the airfoil and a third zone outboard of the second zone, the portion being along the third zone.

19. The method of claim 18 wherein:

the first zone is formed by an alloy having in weight percent 10-13 Cr and 6-12 Ta; and

the second zone is formed by an alloy having in weight percent 5-7 Cr, 5.6-6.4 Al, and at least 16 combined Mo+W+Ta+Re+Ru.

20. The method of claim 13 further comprising:

at least partially during the introduction, cooling the mold so as to solidify the introduced alloy, the varying occurring at least partially during the solidifying.

21. The method of claim 13 wherein:

the blade comprises a nickel-base superalloy.

22. The method of claim 13 wherein:

the blade comprises a single crystal or directionally solidified columnar grain microstructure extending across two zones of different composition and a transition therebetween.

23. The method of claim 13 wherein:

the blade has a density variation of at least 3%.

24. The method of claim 13 wherein:

the introducing and varying comprise;

a bottom-feed pour followed by at least one top feed pour.

25. The method of claim 13 wherein:

the introducing and varying comprise;

a series of top feed pours without any bottom-feed pour.

26. The method of claim 13 wherein:

the introducing and varying comprise;

introducing a first alloy to a mold cavity via along a first flow path through a first port; and

introducing a second alloy, differing in composition from the first alloy, to the mold cavity along a second flow path through a second port but not through the first port.

27. The method of claim 26 wherein:

the first flow path and second flow path partially overlap along a portion of a downsprue.

28. The method of claim 26 wherein:

the first flow path passes through a grain starter and the second flow path bypasses the grain starter.

29. The method of claim 26 wherein:

the first alloy has solidified to block the first port by the time the second alloy is introduced.

30. The method of claim 26 wherein:

the introducing and varying further comprise;

introducing a third alloy, differing in composition from the first alloy and second alloy, to the mold cavity along a third flow path through a third port but not through the first port or second port.

12. An alloy comprising, by weight percent:

nickel as a largest content;

5-8 Cr

0.5-1.0 Mo;

2.5-3.5 W

1.5-2.5 Ta;

5.5-7.5 Al;

4.5-5.5 Co;

0-4 Re; and

0.05-0.20 Hf.