ABSTRACT
The high strength, high modulus continuous filaments showing the most promise for metals have been boron and Borsic, with alumina attractive for its stability at elevated temperatures toward many transition metals such as titanium and nickel. The longitudinal tensile and compressive strengths, creep resistance, and fatigue behavior of metal matrix composites have been excellent. The mechanical properties are quite sensitive to filament-load angle. The transverse properties of unidirectional composites have been low, evidently due to factors such as fiber splitting. Methods of improving transverse strength include development of improved filaments, matrix heat treatment, and use of cross or angle plies. The use of wider diameter boron filaments in boron/aluminum and boron/titanium composites has resulted in a major advance in mechanical properties, and particularly the significant improvement in transverse strengths. Sufficient mechanical property data have been obtained on several metal matrix composite systems to demonstrate that efficient reinforcement can be achieved.
