Low-porosity gamma titanium aluminide cast articles and their preparation
AssigneeGeneral Electric Company
InventorThomas J. Kelly
Life of this patent
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Abstract
The inside surface of the mold used to cast gamma titanium aluminide articles is pretreated with a facecoating of an inoculant such as titanium diboride or titanium carbide. When the molten metal of the composition that produces the gamma titanium aluminide is cast into the mold, the facecoating nucleates grains at the surface of the casting, which inhibits the formation of surface-connected porosity in the casting. Subsequent hot isostatic pressing of the article produces a sounder article than otherwise could be achieved.
Claims17
A method of preparing a gamma titanium aluminide article, comprising the steps of:
- furnishing a mold having an inner surface defining the shape of an article, at least a portion of the inner surface having thereon a facecoating of an inoculant operable to nucleate grains during solidification and to cause an as-cast gamma titanium aluminide material to form a nearly equiaxed structure rather than a columnar structure at the surface of a casting;
- casting into the mold a charge of a molten metal which, upon solidification, forms a gamma titanium aluminide material;
- and
- cooling the cast charge.
A method of preparing a gamma titanium aluminide article, comprising the steps of:
- furnishing a mold having an inner surface defining the shape of an article, at least a portion of the inner surface having thereon a facecoating of an inoculant operable to nucleate grains during solidification and to cause an as-cast gamma titanium aluminide material to form a nearly equiaxed structure rather than a columnar structure at the surface of a casting;
- casting into the mold a charge of a molten metal which, upon solidification, forms a gamma titanium aluminide material;
- cooling the cast charge;
- and thereafter
- hot isostatically pressing the cast and cooled charge.
A method of preparing a gamma titanium aluminide article, comprising the steps of:
- furnishing a mold having an inner surface defining the shape of an article, at least a portion of the inner surface having thereon a facecoating of an inoculant operable to nucleate grains during solidification of a molten metal which, upon solidification, forms a gamma titanium aluminide material;
- casting into the mold a charge of a molten metal which, upon solidification, forms a gamma titanium aluminide material having nearly equiaxed grains at the surface of the casting adjacent to the inner surface of the mold;
- and
- cooling the cast charge.
Dependencies are inferred from the claim text.