Porous metallic product and method for making same

Abstract

This invention pertains to a product and a method for making the product. The product is a lightweight solid porous metallic product containing small solid spheres having a coating of a primary alpha phase thereon disposed in a solid metal alloy eutectic matrix. The method includes the steps of mixing the hollow rigid spheres and a metal alloy, which metal alloy can be preheated to render it molten, in order to form a dispersion of the spheres distributed in the molten alloy; initially cooling the dispersion to render it semi-solid whereby the spheres are coated by a solid and the coated spheres are disposed in the semi-solid mixture of the solid and liquid; and finally cooling the sphere-containing semi-solid mixture to a temperature at which the sphere-containing semi-solid mixture becomes solid and the product is formed.

Description

FIELD OF THE INVENTION [0001] This invention pertains to the field of porous metallic objects and preparation thereof that is characterized by the use of small hollow spheres in a semi-solid mixture in a metal alloy. DESCRIPTION OF THE RELATED ART [0002] Lightweight or porous metallic materials and structures are made in honeycomb and foam core forms. Other examples are linear cellular metals and metal wire trusses. Most of these materials are made in simple shapes such as two-dimensional panels and one-dimensional bars and rods. Making these into complex three-dimensional shapes is very difficult and cost intensive. This is because of the nature of the processing routes for these materials. These materials are expensive to fabricate because they require several processing steps. Honeycomb structures are made by epoxy joining or brazing together a honeycomb arrangement made by folding thin metal ribbons. This forms the honeycomb core to which are joined face panels to make a sandwic...

AI Technical Summary

Benefits of technology

This patent describes a method for making lightweight metallic products using small ceramic or metallic particles to reduce density. The method allows for the creation of net-shape products that do not require significant machining. The resulting products have greater physical properties than expected, such as lower density and higher strength and stiffness. The method involves using a semi-solid metal alloy and cooling it to a semi-liquid state to stabilize the solid and liquid phases. The resulting product has a coating of solid metal alloy on small ceramic or metallic spheres. The technical effects of this patent include improved lightweight metallic products with better physical properties.

Problems solved by technology

Making these into complex three-dimensional shapes is very difficult and cost intensive.

These materials are expensive to fabricate because they require several processing steps.

Some of these materials have good stiffness but lack in other mechanical properties, such as tensile and compressive strengths.

Because of their high fabrication cost, these lightweight materials and structures have been targeted for high-end applications, such as aerospace, propulsion and ballistic protection.

Many of these materials are made abroad and availability thereof is severely restricted.

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