# US 5,346,562 A · Method of production of iron aluminide materials

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- Number: US 5,346,562 A
- Document ID: US5346562A
- Status: Granted
- Kind: A
- Application number: 08/120,718
- Filed: 1993-09-13
- Granted: 1994-09-13
- Earliest claimed: 1992-09-16
- Assignees: Sulzer Innotec AG
- Inventors: Emad Batawi; John Peters
- Web page: https://patentgrep.com/patent/US5346562A

## CPC

- C22C 38/06: containing aluminium
- C22C 32/0068: {only nitrides}
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

The method makes possible the production of iron aluminide raw materials which consist of a Fe.sub.3 Al-base alloy containing 18-35% Al, 3-15% Cr, 0.2-0.5% B and/or C, and altogether 0-8% of the following alloying additives: Mo, Nb, Zr, Y and/or V, as well as iron as dominant remainder. In accordance with the invention additives are added to the melt of a known alloy, from which dispersed crystallites, dispersoids, are formed which thanks to good wettability become upon solidification, embedded in the monocrystalline phase. From the solid alloy, through hot rolling at a temperature between 650.degree. and 1000.degree. C., a fine grain structure may be generated.

## Claims

### Claim 1

A method of producing iron aluminide materials from a Fe.sub.3 Al base alloy comprising 18-35% by atomic weight of Al, 3-15% by atomic weight of Cr, 0.2-0.5% by atomic weight of at least one of B and C, 0-8% by atomic weight of at least one of Mo, Nb, Zr, Y and V, and a remainder consisting of iron, which comprises:
(a) melting the Fe.sub.3 Al base alloy at a melting temperature in a chamber held at vacuum;
(b) adding a protective gas to the chamber producing an atmosphere in the chamber of between 0.2 and 1.0 bar;
(c) adding Ti, Zr and an Fe-Cr alloy containing N to the melted Fe.sub.3 Al base alloy at a temperature 200.degree.-400.degree. K. above the melting temperature, forming dispersoids of (Ti,Zr)N 2-10% by volume which are satisfactorily wettable by the melted Fe.sub.3 Al base alloy so that upon solidification the dispersoids embed in a monocrystalline phase;
(d) pumping the protective gas away after a holding time between 100 and 1000 seconds;
(e) solidifying the melted Fe.sub.3 Al base alloy containing the dispersoids;
(f) hot rolling the solidified Fe.sub.3 Al base alloy containing the dispersoids at a temperature between 650.degree. and 1000.degree. C.; and
(g) annealing the Fe.sub.3 Al base alloy containing the dispersoids at a temperature between 400.degree. and 1000.degree. C.