PLASMA SPRAYED METAL MATRIX FIBER REINFORCED COMPOSITES.

High strength, high modulus boron reinforced metal matrix composites were fabricated by plasma spraying. A new fabrication technique which includes the plasma spraying of monolayer fiber reinforced tapes and the subsequent diffusion bonding of these tapes was found to be an excellent method to insure reproducible properties in the composites. Boron fibers coated with silicon carbide were found to have superior resistance to degradation at elevated temperatures compared to that of boron. The elastic and strength properties of the composites were characterized for unidirectional composites. Strengths of up to 189,000 psi in tension and 297,000 psi in compression were measured for composites with 50% volume fraction BORSIC fiber in aluminum. Other properties measured include fatigue strength, creep, stress rupture, impact resistance, and high temperature strength. Analytical mechanics, fractography, metallographic examination and nondestructive testing were used to better understand the properties of the composite structures. (Author)