Hybrid turbine blade for improved engine performance or architecture

• US 10,005,125 B2
• Filed: 12/13/2013
• Issued: 06/26/2018
• 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): Kerns, Kevin P
• Application Number:
  US14/106,007
• Publication Number:
  US 20140363305A1
• Time in Patent Office: 1,656 Days
• Field of Search: 164 94, 164 95, 164 96, 1641221, 1641222
• 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 includes introducing a molten alloy into a mold. A composition of the introduced alloy is varied during the introduction so as to produce a compositional variation.

Claims

1. A method of casting, comprising:

introducing via a pour cup a first molten alloy into a mold, a downsprue extending downwardly from a base of the pour cup;

partially solidifying the first molten alloy to form a solidified section and block the downsprue, with a remaining molten portion on the solidified section; and

introducing via said pour cup a second molten alloy into the mold such that the remaining molten portion and the second molten alloy at least partially mix, the first molten alloy and second molten alloy differing in chemistry.

2. The method of claim 1 wherein:

the introduction of the second molten alloy is a continuous pour of the second molten alloy to both form the mixture and form a further portion after solidifying the mixture.

3. The method of claim 1 wherein:

the introduction of the second molten alloy comprises;

a first pour of the second molten alloy whereafter the mixture is solidified; and

a second pour onto the solidified mixture and solidifying to form another solidified section such that the solidified mixture metallurgically bonds the solidified sections together.

4. 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 through a pour cup and a downsprue extending downwardly from a base of the pour cup; and

varying a composition of the introduced alloy during the introduction so as to produce a compositional variation, the compositional variation providing a density variation of at least 3%,

wherein;

the introducing and varying comprise;

a bottom-feed pour followed by at least one top-feed pour, both through a single said pour cup, said top feed pour being introduced on or atop an at least partially solidified section of said molten alloy that locally blocks the downsprue.

5. The method of claim 4 wherein:

the compositional variation includes variation along the airfoil.

6. The method of claim 4 wherein:

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

7. The method of claim 4 wherein:

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

8. The method of claim 4 wherein:

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

9. The method of claim 8 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.

10. The method of claim 4 further comprising:

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

11. The method of claim 4 wherein:

the blade has a shroud at the airfoil distal end;

at least a portion of the shroud has a lower density than at least a portion of the airfoil.

12. The method of claim 4 wherein:

the blade comprises a nickel-base superalloy.

13. The method of claim 4 wherein:

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

14. The method of claim 4 wherein:

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

15. 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,

wherein;

the introducing and varying comprise;

introducing a first alloy to a mold cavity 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, wherein the first flow path and second flow path overlap along a portion of a downsprue; and

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

16. The method of claim 15 wherein:

the first flow path and second flow path overlap from a pour cup.

17. The method of claim 15 wherein:

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

18. The method of claim 15 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.