Foamed metal and method of producing same

A method of producing a foamed metal having an apparent specific gravity of from 0.2 to 0.8 and comprising an aggregate of uniform size and uniformly dispersed of polygonal closed cells having an average diameter of from 2 to 10 mm, which comprises adding in a mold a foaming agent and a thickener to a molten metal and agitating the melt, said molten metal being aluminum or an alloy thereof, said thickener being elemental calcium and said foaming agent being titanium hydride, wherein said thickener is added to said molten metal in an amount of from 0.2 to 8% by weight, the melt is agitated to adjust the viscosity of said melt, then powdered titanium hydride is added to the melt in an amount of from 1 to 3% by weight, and the melt is agitated to effect foaming, wherein before said addition of said thickener the entire body of a mold is heated to a temperature not lower than the melting point of said metal to be foamed, thereafter in the process of growth of the foam the mold is closed in the condition in which an air release port is provided, air inside said mold is released to the exterior by expansion of a multiplicity of bubbles generated on thermal decomposition of the foaming agent, said molten metal is permitted to fill up the interior of said mold to close said release port thereby hermetically sealing said mold, the internal pressure of said bubbles in said hermetically sealed mold is increased to form a uniform cellular structure under the balanced internal pressures of said bubbles, the heating of said mold is stopped to cool and solidify said foamed metal.