Dispersion strengthening of metals by in-can processing

Claim 2

A SELF-CONTAINED POWDER METAL MIXTURE ADAPTED TO BE DISPERSION STRENGTHENED BY INTERNAL OXIDATION AND EXTRUDED UNDER HEAT AND PRESSURE, THE SELF-CONTAINED POWDER METAL MIXTURE COMPRISING: AN INTIMATE MIXTURE OF 100 WEIGHT PARTS OF A POWDERED ALLOY AND AT LEAST ABOUT 0.1 WEIGHT PARTS OF AN OXIDANT, SAID POWDERED ALLOY HAVING AN AVERAGE PARTICLE SIZE OF LESS THAN 300 MICRONS AND CONSISTING OF A RELATIVELY NOBLE MATRIX METAL HAVING A NEGATIVE FREE ENERGY OF OXIDE FORMATION AT 25*C OF UP TO 70 KILOCALORIES PER GRAM ATOM OF OXYGEN, AND A SOLUTE METAL HAVING A NEGATIVE FREE ENERGY OF OXIDE FORMATION EXCEEDING THE NEGATIVE FREE ENERGY OF OXIDE FORMATION OF SAID MATRIX METAL BY AT LEAST ABOUT 60 KILOCALORIES PER GRAM ATOM OF OXYGEN AT 25*C, SAID PXIDANT CONSISTING OF AN INTIMATE MIXTURE OF HEAT-REDUCIBLE METAL OXIDE HAVING A NEGATIVE FREE ENERGY OF FORMATION AT 25*C OF UP TO 70 KILOCALORIES PER GRAM ATOM OF OXYGEN AND FINELY DIVIDED HARD, REFRACTORY METAL OXIDE HAVING A NEGATIVE FREE ENERGY OF FORMATION EXCEEDING THE NEGATIVE FREE ENERGY OF FORMATION OF SAID HEAT-REDUCIBLE METAL OXIDE BY AT LEAST ABOUT 60 KILOCALORIES PER GRAM ATOM OF OXYGEN AT 25*C; SAID HEAT-REDUCIBLE METAL OXIDE BEING PRESENT IN SUBSTANTIALLY STOICHIOMETRIC PROPORTION FOR COMPLETE OXIDATION OF SAID SOLUTE METAL IN SAID ALLOY WHEREBY A RESIDU OF HEATREDUCIBLE METAL OXIDE REMAINS IN SAID POWDER METAL MIXTURE AFTER INTERNAL OXIDATION ADAPTED TO BE DISPERSION STRENTHENED DURING COALESCENCE BY SAID HARD, REFRACTORY METAL OXIDE; AND A METAL CONTAINER COMPRISING SIDE WALL PORTIONS, A FORWARD WALL, AND A REWARD WALL SAID WALLS DEFINING A CAVITY WITHIN SAID METAL CONTAINER FOR CONTAINING SAID POWDER METAL MIXTURE OF ALLOY AND OXIDANT FREE FROM CONTAMINATION DURING INTERNAL OXIDATION AND EXTRUSION WHEREBY SAID POWDER METAL MIXTURE IS ADAPTED TO BE DISPERSION STRENGTHENED WITHIN SAID METAL CONTAINER AND DIRECTLY EXTRUDED FROM SAID METAL CONTAINER.

Claim 3

The self-contained powder metal mixture of claim 1 wherein said oxidant exceeds the stoichiometric proportion for complete oxidation of said solute metal to leave reducible oxides of less than 0.1% by weight of oxygen based on the dispersion-strengthened metal mixture.

Claim 4

The self-contained powder metal mixture of claim 1 wherein said walls have a wall thickness greater than one-sixteenth inch.

Claim 5

The self-contained powder metal mixture of claim 1 wherein said container is copper and said noble matrix metal of the alloy is copper.

Claim 6

The self-contained powder metal mixture of claim 1 wherein said container is nickel and said noble matrix metal of the alloy is nickel.

Claim 7

The self-contained powder metal mixture of claim 1 wherein said container is steel and said noble matrix metal of the alloy is iron.

Claim 8

A process for dispersion strengthening a self-contained powder metal mixture and extruding metal stock from the same container, comprising: providing a metal container having a cavity therein for receiving a powder metal mixture adapted to be dispersion strengthened, said metal container for containing the metal mixture during internal oxidation and extrusion; filling said metal container with powder metal mixture comprising about 100 weight parts of a powdered alloy and at least about 0.1 weight parts of an oxidant, said powdered alloy having an average particle size of less than 300 microns and consisting of a relatively noble matrix metal having a negative free energy of oxide formation at 25*C of up to 70 kilocalories per gram atom of oxygen, and a solute metal having a negative free energy of oxide formation exceeding the negative free energy of oxide formation of said matrix metal by at least about 60 kilocalories per gram atom of oxygen at 25*C, said oxidant consisting of an intimate mixture of heat-reducible metal oxide having a negative free energy of formation at 25*C of up to 70 kilocalories per gram atom of oxygen, and finely divided hard, refractory metal oxide having a negative free energy of formation exceeding the negative free energy of formation of said heat-reducible metal oxide by at least about 60 kilocalories per gram atom of oxygen at 25*C, said heat-reducible metal oxide being present in substantially stoichiometric proportion for complete oxidation of all said solute metal in the said alloy; heating said container at a temperature of at least about 1400*F to internally oxidize said solute metal of the alloy and form a residue of heat-reducible metal oxide whereby said alloy is dispersion strengthened; and extruding said dispersion-strengthened alloy from said container under heat and pressure to thermally coalesce said internally oxidize metal mixture and oxidant residue into dispersion-strengthened metal stock whereby said hard, refractory metal oxide dispersion strengthens said residue of heat-reducible metal oxide.

Claim 9

A process for dispersion strengthening a self-contained powder metal mixture and extruding metal stock from the same container, comprising: providing a metal container having a cavity therein for receiving a powder metal mixture adapted to be dispersion strengthened, said metal container for containing the metal mixture during internal oxidation and extrusion; filling said metal container with powder metal mixture comprising about 100 weight parts of a powdered alloy and at least about 0.1 weight parts of an oxidant, said powdered alloy having an average particle size of less than 300 microns and consisting of a relatively noble matrix metal having a negative free energy of oxide formation at 25*C of up to 70 kilocalories per gram atom of oxygen, and a solute metal having a negative free energy of oxide formation exceeding the negative free energy of oxide formation of said matrix metal by at least about 60 kilocalories per gram atom of oxygen at 25*C, said oxidant consisting of an intimate mixture of heat-reducible metal oxide having a negative free energy of formation at 25*C of up to 70 kilocalories per gram atom of oxygen, and finely divided hard, refractory metal oxide having a negative free energy of formation exceeding the negative free energy of formation of said heat-reducible metal oxide by at least about 60 kilocalories per gram atom of oxygen at 25*C, said heat-reducible metal oxide being present in substantially stoichiometric proportion for complete oxidation of all said solute metal in the said alloy; heating said container at a temperature of at least about 1400*F to internally oxidize said solute metal of the alloy and form a residue of heat-reducible metal oxide whereby said alloy is dispersion strengthened; and extruding said dispersion-strengthened alloy from said container under heat and pressure to thermally coalesce said internally oxidize metal mixture and oxidant residue into dispersion-strengthened metal stock whereby said hard, refractory metal oxide dispersion strengthens said residue of heat-reducible metal oxide.

Claim 10

The process of claim 7 wherein oxidant exceeds the stoichiometric proportion required to completely oxidize said solute metal in the alloy whereby less than 0.1% by weight of oxygen of reducible oxides remain after the step of heating to internally oxidize said solute metal of the alloy.