Metal Matrix Composite Technology.

The primary emphasis of the report pertains to the metal matrix composite system aluminum plus boron fiber with a protective coating. Alloys and fibers have been considered which are deemed most useful for aerospace applications. Further research and development will concentrate on composite systems for higher temperature application. It was found that, although environmental attack by salt water could be characterized by the matrix properties, degradation of properties at high temperatures in air 700C were better related to the fibers. The transverse strength of boron-aluminum was related for the most part to the problem of fiber splitting and such effects as matrix, heat treatment, volume fraction fiber, test temperature, test specimen configuration, fiber properties, and secondary reinforcement were studied. Axial, transverse, and cross-ply composites were studied in low-cycle fatigue tests. Charpy V notch bend tests and center-notched tensile tests were investigated to determine the effect of stress concentration factors and general fracture behavior. Author