# US 5,348,702 A · Process for producing .gamma. and .beta. dual phase TiAl based intermetallic compound alloy

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,348,702 A
- Document ID: US5348702A
- Status: Granted
- Kind: A
- Application number: 08/026,707
- Filed: 1993-03-05
- Granted: 1994-09-20
- Earliest claimed: 1991-01-31
- Assignees: Nippon Steel Corporation
- Inventors: Munetsugu Matsuo; Naoya Masahashi; Keizo Hashimoto; Toshihiro Hanamura; Hideki Fujii; Masao Kimura; Youji Mizuhara; Hiroo Suzuki
- Web page: https://patentgrep.com/patent/US5348702A

## CPC

- C22C 14/00: Alloys based on titanium
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

This invention relates to TiAl based intermetallic compound alloy and process for producing; the object of this invention is to improve high temperature deformability. The alloy comprises basic components: Ti.sub.y AlCr.sub.x, wherein 1%.ltoreq.X.ltoreq.5%, 47.5%.ltoreq.Y.ltoreq.52%, and X+2Y.gtoreq.100%, and comprises a fine-grain structure with a .beta. phase precipitated on a grain boundary of equiaxed .gamma. grain having grain size of less than 30 .mu.m, and possessing a superplasticity such that the strain rate sensitivity factors (m value) is 0.40 or more and tensile elongation is 400% or more tested at 1200.degree. C. and a strain rate of 5.times.10.sup.-4 S.sup.-1.

## Claims

### Claim 1

A process for producing .gamma. and .beta. dual phase TiAl based intermetallic compound alloy, which comprises basic compositions in the atomic rate:
Ti.sub.y AlCr.sub.x
wherein
1%.ltoreq.X.ltoreq.5%,
47.5%.ltoreq.Y.ltoreq.52%,
and
X+2Y.gtoreq.100%
which is subjected to homogeneous heat treatment at a temperature between 1000.degree. C. and the solids temperature (.degree.C) for 2 to 100 hours and then applying thermochemical treatment at a temperature of more than 1100.degree. C.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the thermomechanical treatment is an isothermal forging which is carried out at initial strain rate of slower than 5.times.10.sup.-3 s.sup.-1 and at working degree of more than 60% , at temperature of more than 1100.degree. C.

### Claim 3 (depends on 1)

The process according to claim 1, Wherein the thermomechanical treatment is the isothermal forging which is carried out at initial strain rate of between 5.times.10.sup.-4 S.sup.-1 and 5.times.10.sup.-3 S.sup.-1 and at working degree of more than 60% and at temperature of between 1200.degree. C. and the solid phase line temperature (.degree.C.).