Cost-effective solid-state deposition of functionally graded titanium hollow fan blade sheath for improved galvanic corrosion resistance

Patent metadata

Field	Value
Publication number	US-12497974-B2
Application number	US-202418674188-A
Country	US
Kind code	B2
Filing date	May 24, 2024
Priority date	May 24, 2024
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

An airfoil includes an airfoil body and a sheath. The airfoil body includes a first metallic material and the sheath includes a second metallic material. An interface connects the sheath to the airfoil body such that the sheath covers a forward edge of the airfoil body to define an airfoil leading edge. The interface includes bulk metallic glass bonding the sheath to the airfoil body.

First claim

The invention claimed is:

1 . An airfoil comprising:
an airfoil body comprising a first metallic material, wherein the airfoil body comprises a forward edge, a trailing edge aft of the forward edge, a pressure surface extending between the forward edge and the trailing edge, and a suction surface extending between the forward edge and the trailing edge; and a sheath comprising a second metallic material, wherein the sheath comprises: a head section; a first flank connected to the head section and extending aft from the head section; and a second flank connected to the head section and extending aft from the head section; and an interface connecting the sheath to the airfoil body such that the head section of the sheath covers the forward edge of the airfoil body to define an airfoil leading edge, wherein the interface comprises bulk metallic glass bonding the sheath to the airfoil body, and wherein the bulk metallic glass is friction bonded to the airfoil body.

2 . The airfoil of claim 1 , wherein the first metallic material is an aluminum alloy.

3 . The airfoil of claim 2 , wherein the second metallic material is a titanium alloy.

4 . The airfoil of claim 3 , wherein the bulk metallic glass of the interface comprises titanium-based bulk metallic glass.

5 . The airfoil of claim 4 , wherein the titanium alloy comprises titanium-based bulk metallic glass.

6 . The airfoil of claim 4 , wherein the interface further comprises:
a first layer comprising at least one of nickel, silver, and magnesium, wherein the first layer is metallurgically bonded directly to the aluminum alloy of the airfoil body; and a second layer comprising the titanium-based bulk metallic glass, wherein the second layer is metallurgically bonded to the first layer.

7 . The airfoil of claim 4 , wherein the titanium-based bulk metallic glass of the interface is metallurgically bonded directly to the aluminum alloy of the airfoil body.

8 . The airfoil of claim 1 , wherein the sheath is friction bonded to the interface, wherein the bulk metallic glass is friction bonded to the airfoil body without the bulk metallic glass undergoing a phase change, and wherein the sheath is friction bonded to the bulk metallic glass of the interface without undergoing a phase change, and wherein the bulk metallic glass is friction bonded to the airfoil body by at least one of friction stir additive manufacturing and cold spray deposition, and wherein the sheath is friction bonded to the bulk metallic glass of the interface by at least one of friction stir additive manufacturing and cold spray deposition.

9 . A method of forming a fan blade comprising:
forming an airfoil body from an aluminum alloy, wherein the airfoil body comprises a forward edge, a trailing edge aft of the forward edge, a pressure surface extending between the forward edge and the trailing edge, and a suction surface extending between the forward edge and the trailing edge; and forming a sheath on the forward edge of the airfoil body to form a leading edge of the fan blade, wherein forming the sheath comprises: metallurgically bonding a layer of bulk metallic glass to the forward edge of the airfoil body without phase changing the bulk metallic glass in the layer, thereby forming a friction bond between the layer of bulk metallic glass and the airfoil body; forming over the layer of bulk metallic glass a head section, a first flank connected to the head section and extending aft from the head section, and a second flank connected to the head section and extending aft from the head section, and wherein the layer of bulk metallic glass connects the head section, the first flank, and the second flank of the sheath to the airfoil body.

10 . The method of claim 9 , wherein metallurgically bonding the layer of bulk metallic glass to the forward edge of the airfoil body without phase changing the bulk metallic glass in the layer comprises:
friction surface additive manufacturing the layer of bulk metallic glass to the aluminum alloy of the airfoil body at a temperature less than a melting temperature of the bulk metallic glass.

11 . The method of claim 10 , wherein the layer of bulk metallic glass comprises titanium-based bulk metallic glass.

12 . The method of claim 11 , further comprising:
friction surface additive manufacturing the layer of bulk metallic glass to the forward edge of the airfoil body at a temperature less than 50% of the melting temperature of the bulk metallic glass.

13 . The method of claim 12 , wherein forming over the layer of bulk metallic glass the head section, the first flank, and the second flank comprises:
friction surface additive manufacturing at least one layer of titanium alloy over the layer of bulk metallic glass to form an outer surface of the sheath; and machining the outer surface of the sheath.

14 . The method of claim 9 , wherein metallurgically bonding the layer of bulk metallic glass to the forward edge of the airfoil body without phase changing the bulk metallic glass in the layer comprises:
cold spray depositing the layer of bulk metallic glass directly to the aluminum alloy of the airfoil body at a temperature less than a melting temperature of the bulk metallic glass.

15 . The method of claim 14 , wherein the layer of bulk metallic glass comprises titanium-based bulk metallic glass.

16 . The method of claim 15 , wherein forming over the layer of bulk metallic glass the head section, the first flank, and the second flank comprises:
cold spray depositing at least one layer of titanium alloy over the layer of bulk metallic glass to form an outer surface of the sheath; and machining the outer surface of the sheath.

17 . The method of claim 9 , wherein metallurgically bonding the layer of bulk metallic glass to the forward edge of the airfoil body without phase changing the bulk metallic glass in the layer comprises:
friction surface additive manufacturing an isolative layer directly to the aluminum alloy of the airfoil body at the forward edge at a temperature less than a melting temperature of the isolative layer, wherein the isolative layer comprises at least one of nickel, silver, and magnesium; and friction surface additive manufacturing the layer of bulk metallic glass to the isolative layer at a temperature less than a melting temperature of the bulk metallic glass such that the isolative layer metallurgically bonds the layer of bulk metallic glass to the forward edge of the airfoil body.

18 . The method of claim 17 , wherein the layer of bulk metallic glass comprises titanium-based bulk metallic glass.

19 . The method of claim 9 , wherein metallurgically bonding the layer of bulk metallic glass to the forward edge of the airfoil body without phase changing the bulk metallic glass in the layer comprises:
cold spray depositing an isolative layer directly to the aluminum alloy of the airfoil body at the forward edge at a temperature less than a melting temperature of the isolative layer, wherein the isolative layer comprises at least one of nickel, silver, and magnesium; and cold spray depositing the layer of bulk metallic glass to the isolative layer at a temperature less than a melting temperature of the bulk metallic glass such that the isolative layer metallurgically bonds the layer of bulk metallic glass to the forward edge of the airfoil body.

20 . The method of claim 19 , wherein the layer of bulk metallic glass comprises titanium-based bulk metallic glass.

Assignees

• Rtx Corp

Inventors

• El-Wardany Tahany
• Martinez Sonia
• Bedard Benjamin

Classifications

• F05D2300/604

  Amorphous · CPC title

• F05D2300/174

  Titanium alloys, e.g. TiAl · CPC title

• F05D2240/303

  related to the leading edge of a rotor blade · CPC title

• F05D2230/31

  Layer deposition · CPC title

• F05D2220/36

  specially adapted for the fan of turbofan engines · CPC title