Title: Polymer quenched prealloyed metal powder

Abstract

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3 % Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder priormore » to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.« less

Inventors:

Hajaligol, Mohammad R ^[1]; Fleischhauer, Grier ^[1]; German, Randall M ^[2]

---

+ Show Inventor Affiliations

1. Midlothian, VA
2. State College, PA

Issue Date:

2001-01-01

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

OSTI Identifier:

874011

Patent Number(s):

6293987

Assignee:

Chrysalis Technologies Incorporated (Richmond, VA)

Patent Classifications (CPCs):

B - PERFORMING OPERATIONS B22 - CASTING B22F - WORKING METALLIC POWDER

C - CHEMISTRY C21 - METALLURGY OF IRON C21D - MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS

Show more

B - PERFORMING OPERATIONS B22 - CASTING B22F - WORKING METALLIC POWDER

B22F2009/0824 - {with a specific atomising fluid}
B22F9/082 - {atomising using a fluid

C - CHEMISTRY C21 - METALLURGY OF IRON C21D - MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS

C21D8/0273 - {Final recrystallisation annealing}

B - PERFORMING OPERATIONS B22 - CASTING B22F - WORKING METALLIC POWDER

B22F3/24 - After-treatment of workpieces or articles {
B22F3/18 - by using pressure rollers
B22F3/16 - in successive or repeated steps

C - CHEMISTRY C21 - METALLURGY OF IRON C21D - MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS

C21D8/0205 - {of ferrous alloys}

C - CHEMISTRY C22 - METALLURGY C22C - ALLOYS

C22C33/0278 - {with at least one alloying element having a minimum content above 5%}

B - PERFORMING OPERATIONS B22 - CASTING B22F - WORKING METALLIC POWDER

B22F2009/088 - {Fluid nozzles, e.g. angle, distance}
B22F5/006 - {of flat products, e.g. sheets
B22F3/115 - by spraying molten metal, i.e. spray sintering, spray casting

C - CHEMISTRY C21 - METALLURGY OF IRON C21D - MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS

C21D8/0236 - {Cold rolling}

B - PERFORMING OPERATIONS B22 - CASTING B22F - WORKING METALLIC POWDER

B22F2003/248 - {Thermal after-treatment}
B22F2998/10 - Processes characterised by the sequence of their steps

C - CHEMISTRY C22 - METALLURGY C22C - ALLOYS

C22C1/0491 - {comprising intermetallic compounds

Show less

DOE Contract Number:  

AC05-84OR21400

Resource Type:

Patent

Country of Publication:

United States

Language:

English

Subject:

polymer; quenched; prealloyed; metal; powder; metallurgical; process; preparing; sheet; intermetallic; alloy; composition; iron; nickel; titanium; aluminide; manufactured; electrical; resistance; heating; elements; improved; temperature; ductility; resistivity; cyclic; fatigue; oxidation; strength; sagging; entirely; ferritic; microstructure; free; austenite; weight; 32; optional; additions; ltoreq; gtoreq; 05; zr; 75; submicron; oxide; particles; electrically; insulating; conductive; covalent; ceramic; rare; earth; cu; forming; non-densified; consolidating; roll; compaction; tape; casting; plasma; spraying; cold; rolled; rolling; increase; density; reduce; thickness; annealing; water; gas; atomized; subjecting; sieving; blending; binder; prior; consolidation; step; partially; sintered; steps; repeated; achieve; desired; properties; carried; vacuum; furnace; inert; atmosphere; final; recrystallizes; average; grain; size; 10; 30; stress; relief; b2; phase; range; temperature sagging; metallic alloy; average grain; optional additions; atomized powder; gas atomized; entirely ferritic; fatigue resistance; ferritic microstructure; conductive covalent; cyclic fatigue; covalent ceramic; vacuum furnace; temperature strength; heating elements; resistance heating; alloy composition; intermetallic alloy; plasma spray; oxidation resistance; temperature ductility; heating element; ceramic particles; electrically insulating; temperature range; electrically conductive; rare earth; metal sheet; grain size; earth metal; electrical resistance; inert atmosphere; electrical resistivity; plasma spraying; oxide particles; iron aluminide; metal powder; titanium aluminide; cold rolled; cold rolling; annealing steps; powder metallurgical; ceramic particle; tape casting; temperature oxidation; rolled sheet; annealing step; metallurgical process; sheet thickness; phase temperature; roll compaction; stress relief; consolidation step; resistance heat; oxide particle; tape cast; prealloyed metal; /75/