Casting Routes for Porous Metals Production

Abstract

Casting Routes for Porous Metals Production The last decade has seen growing interest in professional public about applications of porous metallic materials. Porous metals represent a new type of materials with low densities, large specific surface, and novel physical and mechanical properties, characterized by low density and large specific surface. They are very suitable for specific applications due to good combination of physical and mechanical properties such as high specific strength and high energy absorption capability. Since the discovery of metal foams have been developed many methods and techniques of production in liquid, solid and gas phases. Condition for the use of metal foams - advanced materials with unique usability features, are inexpensive ways to manage their production. Mastering of production of metallic foams with defined structure and properties using gravity casting into sand or metallic foundry moulds will contribute to an expansion of the assortment produced in foundries by completely new type of material, which has unique service properties thanks to its structure, and which fulfils the current demanding ecological requirements. The aim of research conducted at the department of metallurgy and foundry of VSB-Technical University Ostrava is to verify the possibilities of production of metallic foams by conventional foundry processes, to study the process conditions and physical and mechanical properties of metal foam produced. Two procedures are used to create porous metal structures: Infiltration of liquid metal into the mold cavity filled with precursors or preforms and two stage investment casting.

Optimization of the annealing of plaster moulds for the manufacture of metallic foams with an irregular cell structure

“…Some technologies are similar to those for polymer foaming, others are developed with regard to the characteristic properties of metallic materials, such as their ability to be sintered or the fact that they can be deposited electrolytically. 1 According to the state, in which a metal is processed, the manufacturing processes can be divided into four groups. Porous metallic materials can be made from: 2,3 • a liquid metal (e.g., direct foaming with gas, blowing agents, powder-compact melting, casting, spray forming) • a powdered metal (e.g., sintering of powders, fibres or hollow spheres, extrusion of polymer/metal mixtures, reaction sintering)…”

Development of Salt Core Use Alternative in Aluminum Alloy Casting Parts

“…The geometries of casting parts used in the automotive industry are quite complex. In casting molds of complex parts, steel cores (sliders ) are often not sufficient in terms of both castability and casting quality [1,2]. Sand cores are generally used in the production of parts with complex structures and internal cavities, where steel cores cannot be used.…”

“…Sand cores are generally used in the production of parts with complex structures and internal cavities, where steel cores cannot be used. Sand cores are produced by cold-box (polyurethanes as binders) or hot box (alkali silicates) method [2]. The use of salt cores instead of sand cores has been known and developed since the end of the 20th century, especially in the field of gravity and low pressure die casting work continues [3][4][5][6][7][8][9].…”

Lost Cores for High-Pressure Die Casting

“…Classic metal cores used for high-pressure casting of castings cannot entirely cover increasingly growing demands for shape complexity of castings especially for automobile industry [1,2]. Therefore the interest in development of soluble cores (Verlorene Kerne, Lost Cores) that would also enable at the same time the closed technological cycle is growing.…”