Reinforcement preform and metal matrix composites including the reinforcement preform

摘要

A preform for use in a metal matrix composite, particularly for a magnesium metal composite, and a metal matrix composite, typically made by squeeze casting, using the preform. In the preform the reinforcing material typically is silicon carbide, boron nitride, carbon or graphite. The binder used in the preform is magnesium fluoride, which avoids the known problems which result from the high reactivity of magnesium metal with other binders, such as silica and alumina, which results in the formation of magnesium oxide in the reinforced composite. The presence of magnesium oxide crystals in the metal matrix adversely affects the properties of the composite.