Production of High Strength Aluminium Alloys by Extrusion of Atomized Powders

Abstract

The mechanism of powder consolidation in the extrusion chamber is analysed and it is shown that theoretically the specific pressures required to extrude initial powder compacts will be lower than an equivalent cast billet. The hot working range of metals is thus enlarged and inherently stiffer materials may be extruded. The extrusion of Al alloys from air atomized powders is described and the conditions required for meaningful increases in properties elaborated. The production of Al alloys reinforced by glass is also described and it is shown that although strength levels may be enhanced this type of reinforcement does not lead to a product having a combination of properties significantly more attractive than the cast and wrought product. Consideration is given to other forms of reinforcement. The extrusion of rapidly solidified AI10Mg powder shows that this non-heat treatable alloy has properties comparable with the strongest heat treatable Al alloy. PMj0257