Ordered iron aluminide alloys having an improved room-temperature ductility and method thereof

Claim 3

The method of claim 1 wherein said iron aluminide intermetallic alloy comprises an alloy based on the composition Fe 3 Al.

Claim 4

The method of claim 2 wherein greater than 95% of said elongated grains in said elongated grain structure have an aspect ratio greater than about 20.

Claim 5

The method of claim 2 wherein said iron aluminide intermetallic alloy is heated at a temperature in the range of 650° C. to 800° C.

Claim 6

The method of claim 2 wherein said iron aluminide intermetallic alloy is held at said temperature for a period of time in the range of 15 minutes to 2 hours.

Claim 9

The method of claim 6 wherein said alloy is heated in the temperature range of 650° C. to 800° C. for a period of time in the range of 15 minutes to 2 hours.

Claim 10

The method of claim 6 wherein said alloy is heated in the temperature range of 700° C. to 750° C. for a period of time in the range of 15 minutes to 2 hours.

Claim 11

A new method for improving the room temperature ductility and strength of an iron aluminide intermetallic alloy comprising: a) thermomechanically working an alloy consisting essentially of 25 to 31 at. % aluminum, up to a total of about 12 at. % of an element or combination of elements selected from the class consisting of Cr, Zr, Nb, Mo, B, C, and mixtures thereof, and the balance iron, by means which produce an elongated grain structure, the elongated grains making up said elongated grain structure being oriented generally in the primary working direction, greater than 95% of said elongated grains having an aspect ratio greater than about 20; b) heating said alloys at a temperature in the range of 650° C. to 800° C. for a period of time in the range of 15 minutes to 2 hours to produce a B2-type crystal structure; and c) quenching said alloys in oil to retain said B2-type crystal structure to provide alloys having improved room temperature ductility and strength.

Claim 12

A new method for improving the room temperature ductility and strength of an iron aluminide intermetallic alloy comprising: a) thermomechanically working an alloy consisting essentially of 25 to 31 at. % aluminum, up to a total of about 12 at. % of an element or combination of elements selected from the class consisting of Cr, Zr, Nb, Mo, B, C, and mixtures thereof, and the balance iron, by means which produce an elongated grain structure, the elongated grains making up said elongated grain structure being oriented generally in the primary working direction, greater than 95% of said elongated grains having an aspect ratio greater than about 20; b) heating said alloys at a temperature in the range of 650° C. to 800° C. for a period of time in the range of 15 minutes to 2 hours to produce a B2-type crystal structure; and c) quenching said alloys in oil to retain said B2-type crystal structure to provide alloys having improved room temperature ductility and strength.

Claim 13

The method of claim 9 wherein said thermomechanical working is achieved by any one of extrusion, drawing, rolling and mixtures thereof.

Claim 14

An improved ordered iron aluminide intermetallic alloy product having improved room temperature ductility and strength made by the process comprising: a) thermomechanically working said alloy by means which produce an elongated grain structure, the elongated grains in said elongated grain structure being oriented generally in the primary working direction and greater than 95% of said elongated grains having an aspect ratio greater than about 20; b) heating said alloys at a temperature and for a period of time sufficient to produce a B2-type crystal structure; and c) rapidly cooling said alloys in a moisture-free medium, retaining said B2-type crystal structure to provide alloys having improved room temperature ductility and strength.

Claim 15

An improved ordered iron aluminide intermetallic alloy product having improved room temperature ductility and strength made by the process comprising: a) thermomechanically working said alloy by means which produce an elongated grain structure, the elongated grains in said elongated grain structure being oriented generally in the primary working direction and greater than 95% of said elongated grains having an aspect ratio greater than about 20; b) heating said alloys at a temperature and for a period of time sufficient to produce a B2-type crystal structure; and c) rapidly cooling said alloys in a moisture-free medium, retaining said B2-type crystal structure to provide alloys having improved room temperature ductility and strength.