Nippon Steel Corporation

Naoya Masahashi

Munetsugu Matsuo

Youji Mizuhara

Toshihiro Hanamura

Kenichi Miyazawa

Toshiaki Mizoguchi

Masao Kimura

Hideki Fujii

Hiroo Suzuki

Keizo Hashimoto

TiAl-besed intermetallic compound alloys contain chromium and consist essentially of a dual-phase microstructure of .gamma. and .beta. phases, with the .beta. phase precipitating at .gamma. grain boundaries. The .beta. phase precipitating at .gamma. grain boundaries is 2% to 25% by volume fraction. A process for preparing TiAl-based intermetallic compound alloys comprises the steps of preparing a molten TiAl-based intermetallic compound alloy of a desired composition, solidifying the molten alloy, homogenizing the solidified alloy by heat treatment, and thermomechanically working the homogenized alloy.

TiAl-based intermetallic compound alloys and processes for preparing the

TiAl-based intermetallic compound alloys contain chromium and consist essentially of a dual-phase microstructure of .gamma. and .beta. phases, with the .beta. phase precipitating at .gamma. grain boundaries. The .beta. phase precipitating at .gamma. grain boundaries is 2% to 25% by volume fraction. A process for preparing TiAl-based intermetallic compound alloys comprises the steps of preparing a molten TiAl-based intermetallic compound alloy of a desired composition, solidifying the molten alloy, homogenizing the solidified alloy by heat treatment, and thermomechanically working the homogenized alloy.

Tial-based intermetallic compound alloys and processes for preparing the

Tial-based intermetallic compound alloys having superplasticity

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.

Process for producing .gamma. and .beta. dual phase TiAl based

Ti-A1 intermetallic compound sheet and method of producing same

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.

.gamma. and .beta. dual phase TiAl based intermetallic compound alloy

A continuous thin sheet of a TiAl intermetallic compound consisting of from 35 to 44 wt % Al and the balance Ti and unavoidable impurities, having a thickness of from 0.2 to 3 mm, and having a solidified, as-cast structure comprising columnar crystals extending from both surfaces of the sheet toward the center of the sheet thickness, and a process for producing the same by using a twin-roll type continuous casting procedure.

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Kawasaki, Japan

Naoya Masahashi