Abstract: A process of producing an article having a surface provided with an optical diffraction grating such that the surface generates visible color when illuminated with diffuse white light. The process involves deforming a starting material to produce the article having the surface and, during the deforming step, impressing a diffraction relief pattern on the surface by a tool provided with a bearing surface having a corresponding surface relief pattern of parallel lines that contacts the surface of the article under pressure. While the diffraction relief patter is being impressed, the surface is caused to slide in a direction of movement relative to the bearing surface of the tool. The invention also relates to the article.

Abstract: The invention relates to a process for producing a particle-stabilized metal foam from a composite capable of acting as a precursor composite for the metal foam. The precursor composite is formed by heating a matrix metal, e.g. aluminum or an aluminum alloy, above its liquidus temperature to form a liquid matrix metal, adding to the liquid matrix metal stabilizer particles capable of remaining dispersed within the matrix metal, e.g. MgO particles preferably in the form of agglomerates of particles and some fine particles, and mixing the liquid matrix metal and stabilizer particles under a covering gas, e.g. air, in such a way that bubbles of the gas, as well as the stabilizing particles, are dispersed throughout the matrix metal. The precursor composite can then be foamed by the introduction of a gas by a known technique to form a particle-stabilized metal foam.

Abstract: A process and apparatus are described for manufacturing particle stabilized foamed metal slabs. A foam is first formed in a foaming chamber by heating a composite of a metal matrix and finely divided solid stabilizer particles above the solidus temperature of the metal matrix and discharging gas bubbles into the molten metal composite below the surface thereof to thereby form a stabilized liquid foam on the surface of the molten metal composite. The stabilized liquid foam is continuously drawn off the surface of the molten metal composite and is solidified into a shaped foam product while being continuously drawn off.

Abstract: A novel lightweight gas metal composite is produced having isolated particle stabilized pores. A composite of a metal matrix, e.g. aluminum, and finely divided solid stabilizer particles, e.g. silicon carbide, is heated above the liquidus temperature of the metal matrix and this is mixed such that a vortex is formed. The molten composite is blanketed with a gas and during the vortex mixing. This gas is drawn into the melt to produce an expanded, viscous molten composite material containing pores which are very small, spherical-shaped and quite evenly distributed. The viscous molten composite material can be directly formed into a solid shaped product and is also capable of being remelted and formed by forming processes without destroying the integrity of the pores. The result is a lightweight expanded metal product capable of being formed into shapes to close dimensional tolerances.

Abstract: A process for coloring a metal surface and colored metal products thus produced. The process involves forming a layer of a metal oxide on a surface of the metal to be colored and then bringing about permanent plastic deformation of the surface. If the oxide layer is of a suitable thickness (e.g. 500.ANG.-1 .mu.m) and the deformation is sufficiently high (preferably producing a reduction in thickness of the metal article by 30% or more), the resulting metal article exhibits an attractive color (usually a dichroic pastel color). The article can then be fabricated into finished articles, e.g. beverage cans, in the usual way.

Abstract: A method is described for producing foamed metal in which gaseous bubbles are retained within a mass of molten metal during foaming. The method comprises heating a composite of a metal matrix and finely divided solid stabilizer particles above the liquidus temperature of the metal matrix, discharging gas bubbles into the molten metal composite below the surface thereof to thereby form a foamed melt on the surface of the molten metal composite and cooling the foamed melt thus formed below the solidus temperature of the melt to form a solid foamed metal having a plurality of closed cells. A novel foamed metal product is also described.

Abstract: A method is described for producing foamed metal in which gaseous bubbles are retained within a mass of molten metal during foaming. The method comprises heating a composite of a metal matrix and finely divided solid stabilizer particles above the liquidus temperature of the metal matrix, discharging gas bubbles into the molten metal composite below the surface thereof to thereby form a foamed melt on the surface of the molten metal composite and cooling the foamed melt thus formed below the solidus temperature of the melt to form a solid foamed metal having a plurality of closed cells.