Metal matrix composites

Abstract

A method of forming a metal matrix composite component comprises: providing a body defining a mould cavity; covering a first surface of the mould cavity with a first reinforcement material; restraining the first reinforcement material relative to the body to restrict movement of the first reinforcement material in the mould cavity; adding a second reinforcement material to the mould cavity, the second reinforcement material being in contact with the first reinforcement material; adding molten metal to the mould cavity such that the first reinforcement material and the second reinforcement material become embedded in a continuous metal matrix when the molten metal solidifies.

Description

TECHNICAL FIELD[0001]The present invention relates generally to a method of forming a metal matrix composite component, and particularly but not exclusively to forming a multi-phase metal matrix component.BACKGROUND ART[0002]Metal matrix composites (MMCs) are composed of a metal matrix and a reinforcement, or filler material, which confers excellent mechanical performance, and can be classified according to whether the reinforcement is continuous (monofilament or multifilament) or discontinuous (particle, whisker, short fibre or other). The principal matrix materials for MMCs are aluminium and its alloys. To a lesser extent, magnesium and titanium are also used, and for several specialised applications a copper, zinc or lead matrix may be employed. MMCs with discontinuous reinforcements are usually less expensive to produce than continuous fibre reinforced MMCs, although this benefit is normally offset by their inferior mechanical properties. Consequently, continuous fibre reinforce...

AI Technical Summary

Benefits of technology

This patent describes a method for making a metal matrix composite component that has a seamless transition from one region to another without a boundary interface between them. The first region is reinforced by a first reinforcement material, and the second region is reinforced by a second reinforcement material. This results in a multi-phase component with uniform strength and stiffness. The molten metal used to make the component is aluminium or an aluminium alloy. The composition of the component is designed to maximize stiffness and strength while minimizing weight. The surface region is designed to provide more stiffness and strength than the core material, while the core region is designed to space the surface region from the central axis of the component. Overall, this method provides a way to make a strong and lightweight metal matrix composite component.

Problems solved by technology

Despite the two distinct regions, a single metal matrix infiltrates and extends throughout both regions, providing a seamless transition from one region to the other without a boundary interface therebetween with an inherent weakness, caused for example by an oxide layer which may be found in a conventional physical joint.

In the resulting metal matrix composite component, uniformity in positioning of the first reinforcement material may be important to structural integrity: localized variations in depth of the first reinforcement material from one external surface may cause localized weaknesses in strength and / or stiffness.

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