THE MECHANICAL-PROPERTIES OF AL-ALLOYS REINFORCED WITH CONTINUOUS AL2O3 FIBERS

The mechanical properties of aluminum matrix composites unidirectionally reinforced with Al2O3 fibers have been measured and characterized in longitudinal and transverse tension, as well as in shear. The flow strengths in transverse tension and shear are found to exceed those of the matrices, although the ductilities are lower. The strengthening is generally consistent with the development of plastic constraint in the matrix around well-bonded fibers, subject to the in situ properties of the matrix being known from independent measurements. The properties in longitudinal tension are found to involve interactions between fibers, such that fiber bundle strengths are not achieved, even when a low strength, pure Al matrix is used. Instead, the strengths are consistent with a crack growth controlled failure mechanism, wherein the strength is governed by the resistance of the material to crack extension from failed fibers.