Method of making foamed metal

Claim 1

A METHOD OF MAKING A LIGHTWEIGHT, POROUS METALLIC STRUCTURE COMPRISING THE STEPS OF: COMPACTING AT A PRESSURE OF AT LEAST ABOUT 5 TONS PER SQ. IN. A MIXTURE CONTAINING AT LEAST ABOUT 90 WEIGHT PERCENT OF A POWDERED STRUCTURAL METALLIC MATERIAL AND A POWDERED MATERIAL WHICH RELEASE A SUBSTANTIAL AMOUNT OF GAS AT ABOUT THE MELTING TEMPERATURE OF THE STRUCTURAL METALLIC MATERIAL AND WHICH IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF CALCIUM CARBONATE, ZIRCONIUM HYDRIDE AND TITANIUM HYDRIDE; EXTRUDING THE RESULTING COMPACT AT AN EXTRUSION RATIO OF AT LEAST 8:1 AND AT A TEMPERATURE OF AT LEAST ABOUT 750* F. BUT BELOW THE MELTING POINT OF THE STRUCTURAL METALLIC MATERIAL TO FORM AN EXTRUDED ROD OF THE STRUCTURAL METALLIC MATERIAL AND THE POWDERED MATERIAL; PROGRESSIVELY HEATING THE RESULTING EXTRUDED ROD AT A HEATING RATE OF FROM ABOUT 20 TO ABOUT 130 FAHRENHEIT DEGREES PER SECOND TO AT LEAST ABOUT THE MELTING TEMPERATURE OF THE STRUCTURAL METALLIC MATERIAL TO PRODUCE A FOAM; AND RAPIDLY COOLING THE RESULTING FOAMED MATERIAL TO FORM A LIGHTWEIGHT POROUS STRUCTURE OF A UNIFORM PORE SIZE HAVING A BULK DENSITY OF ABOUT 0.45 TO 0.55 GRAM PER CC.