TiAl-based intermetallic compound alloys and processes for preparing the same
AssigneeNippon Steel Corporation
InventorsNaoya Masahashi, Youji Mizuhara, Munetsugu Matsuo
Life of this patent
Estimating the term…
Abstract
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.
Claims12
A process for preparing a TiAl-based intermetallic compound alloy containing chromium and consisting essentially of a dual-phase microscructure of .gamma. phase and 2% to 25% by volume fraction of .beta. phase precipitating at .gamma. grain boundaries, the alloy being prepared as an intermediate product for manufacturing a TiAl-based intermetallic compound alloy consisting essentially of a dual-phase microstructure of .alpha.2 and .gamma. phases comprising the steps of:
- preparing a molten TiAl-based intermetallic compound alloy consisting essentially of a composition whose atomic fraction is expressed as:
- Ti.sub.a Al .sub.100-a-b Cr.sub.b
- where
- 1.ltoreq.b.ltoreq.5
- 47.5.ltoreq.a.ltoreq.52
- 2a+b.gtoreq.100
- solidifying the molten alloy;
- homogenizing the solidified alloy by heat treatment;
- and causing the .beta. phase to precipitate at .gamma. grain boundaries by applying thermomechanical heat treatment to the homogenized alloy.
A process for preparing a TiAl-based intermetallic compound alloy containing chromium and consisting essentially of a dual-phase microstructure of .gamma. and .beta. phases comprising the steps of:
- preparing a molten TiAl-based intermetallic compound alloy consisting essentially of a composition whose atomic fraction is expressed as:
- Ti.sub.a Al.sub.100-a b-c Cr.sub.b X.sub.c
- X:Nb, Mo, Hf, Ta, W, V
- where
- 47.5.ltoreq.a.ltoreq.52
- 1.ltoreq.b.ltoreq.5
- 0.5.ltoreq.c.ltoreq.3
- b.gtoreq.c
- 2a+b+c.gtoreq.100
- solidifying the molten alloy;
- homogenizing the solidified alloy by heat treatment;
- and causing the .beta. phase to precipitate at .gamma. grain boundaries by applying thermomechanical heat treatment to the homogenized alloy.
A process for preparing a TiAl-based intermetallic compound alloy containing chromium and consisting essentially of a dual-phase microstructure of .gamma. and .beta. phases comprising the steps of:
- preparing a molten TiAl-based intermetallic compound alloy consisting essentially of a composition whose atomic fraction is expressed as:
- Ti.sub.a Al.sub.100-a-b-d Cr.sub.b Y.sub.d
- Y:Si, B
- where
- 47.5.ltoreq.a.ltoreq.52
- 1.ltoreq.b.ltoreq.5
- 0.1 .ltoreq.d.ltoreq.2
- 2a+b+d.gtoreq.100
- solidifying the molten alloy;
- homogenizing the solidified alloy by heat treatment;
- and causing the .beta. phase to precipitate at .gamma. grain boundaries by applying thermomechanical heat treatment to the homogenized alloy.
A process for preparing a TiAl-based intermetallic compound alloy containing chromium and consisting essentially of a dual-phase microstructure of .gamma. and .beta. phases comprising the steps of:
- preparing a molten TiAl-based intermetallic compound alloy consisting essentially of a composition whose atomic fraction is expressed as:
- Ti.sub.a Al.sub.100-a-b-c-d Cr.sub.b X.sub.c Y.sub.d
- X:Nb, Mo, Hf, Ta, W, V
- Y:Si, B
- where
- 47.5.ltoreq.a.ltoreq.52
- 1.ltoreq.b.ltoreq.5
- 0.5.ltoreq.c.ltoreq.3
- b.gtoreq.c
- 0.1.ltoreq.d.ltoreq.2
- 2a+b+c+d.gtoreq.100
- solidifying the molten alloy;
- homogenizing the solidified alloy by heat treatment;
- and causing the .beta. phase to precipitate at .gamma. grain boundaries by applying thermomechanical heat treatment to the homogenized alloy.
Dependencies are inferred from the claim text.