# US 11,078,563 B2 · TiAl alloy and method of manufacturing the same

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- Number: US 11,078,563 B2
- Document ID: US11078563B2
- Status: Granted
- Kind: B2
- Application number: 16/212,997
- Filed: 2018-12-07
- Published: 2019-04-11
- Granted: 2021-08-03
- Earliest claimed: 2016-09-02
- Assignees: IHI Corporation
- Applicants: IHI Corporation
- Inventors: Keiji Kubushiro; Satoshi Takahashi
- Web page: https://patentgrep.com/patent/US11078563B2

## CPC

- C22F 1/183: {of titanium or alloys based thereon}
- C22C 14/00: Alloys based on titanium
- C22F 1/02: in inert or controlled atmosphere or vacuum (adjusting the composition of the atmosphere C21D1/76)
- F01D 5/28: Selecting particular materials; {Particular measures relating thereto;} Measures against erosion or corrosion
- F01D 5/282: {Selecting composite materials, e.g. blades with reinforcing filaments}
- F05D 2220/323: for aircraft propulsion, e.g. jet engines
- F05D 2240/24: for turbines
- F05D 2300/174: Titanium alloys, e.g. TiAl
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

A TiAl alloy for forging, contains 41 at % or more and 44 at % or less of Al, 4 at % or more and 6 at % or less of Nb, 4 at % or more and 6 at % or less of V, 0.1 at % or more and 1 at % or less of B, and the balance being Ti and inevitable impurities.

## Claims

### Claim 1

A TiAl alloy, consisting of:
Ti;
Al in a range of from 41 to 44 at. %;
Nb in a range of from 4 to 6 at. %;
V in a range of from 4 to 6 at. %;
B in a range of from 0.5 to 1 at. %; and
inevitable impurities,
wherein the alloy is suitable for forging,
wherein the alloy has a composition which does not pass through an α-Ti single phase region between a melting point and a room temperature,
wherein the alloy comprises a metal structure having a crystal grain size of 200 μm or less, and
wherein the metal structure consists of a lamellar grain formed from an α2 phase of Ti3Al and a γ phase of TiAl; a γ grain of TiAl; a B2 type grain of TiAl or a β grain of TiAl; borides with a particle size of 0.1 μm or less precipitated in the γ grain, and/or the B2 type grain or the β grain; and inevitable impurities.

### Claim 2 (depends on 1)

The alloy of claim 1, wherein relative to a total of only the volume fraction of the lamellar grain, the volume fraction of the γ grain, and the volume fraction of the B2 type grain or the β grain being 100 vol. %:
the lamellar grain in a volume fraction in a range of from 80 to 95 vol. %;
the γ grain in a volume fraction of from 2 to 10 vol. %, and
the B2 type grain or the β grain in a volume fraction of from 3 to 10 vol. %.

### Claim 3 (depends on 1)

The alloy of claim 1, wherein the metal structure consists of:
a lamellar grain formed from an α2 phase of Ti3Al and a γ phase of TiAl;
a γ grain of TiAl;
a β grain of TiAl;
borides with a particle size of 0.1 μm or less precipitated in the γ grain and/or the β grain; and
inevitable impurities.

### Claim 4 (depends on 3)

The alloy of claim 3, wherein relative to a total of only the volume fraction of the lamellar grain, the volume fraction of the γ grain, and the volume fraction of the β grain being 100 vol. %:
the lamellar grain in a volume fraction of from 80 to 95 vol. %;
the γ grain in a volume fraction of from 2 to 10 vol. %, and
the β grain in a volume fraction of from 3 to 10 vol. %.

### Claim 5 (depends on 1)

The alloy of claim 1, wherein the borides are needle-shaped and comprise TiB and TiB2.

### Claim 6 (depends on 1)

The alloy of claim 1, wherein the Al is present in a range of from 41 to 43 at. %.

### Claim 7 (depends on 1)

The alloy of claim 1, wherein the Al is present in a range of from greater than 43 to less than 44 at.%.

### Claim 8 (depends on 1)

The alloy of claim 1, wherein the Nb is present at 4 at. %.

### Claim 9 (depends on 1)

The alloy of claim 1, wherein the V is present in a range of from 4 to 5 at. %.

### Claim 10 (depends on 1)

The alloy of claim 1, wherein the V is present in a range of from greater than 5 to 6 at. %.

### Claim 11 (depends on 1)

A forged part, comprising the alloy of claim 1.

### Claim 12 (depends on 1)

A forged engine component, comprising the alloy of claim 1.

### Claim 13 (depends on 1)

A forged aircraft engine turbine blade, comprising the alloy of claim 1.