Effects of interfacial bonding on spallation in metal-matrix composites

Two metal-matrix composite systems are studied to determine the influence of inclusions on the spallation strength in plate-impact experiments. The first is an aluminum/ceramic system with several volume fractions of ceramic inclusion, and the second is a copper/niobium composite consisting of 15 vol. % niobium particles embedded in the copper matrix. Plate-impact experiments produce peak compressive stresses of ∼5 GPa in the aluminum/ceramic system and ∼10 GPa in the copper/niobium system. The characteristic code CHARADE is used to calculate detailed compression-release profiles in the composite systems, thus accurately quantifying the wave-evolution occurring between the spall plane and the particle velocity (VISAR) measurement at the rear free surface. The aluminum/ceramic system exhibits a strong dependence of the spall strength on inclusion concentration and morphology. In the case of the copper/niobium system, the spall strength remains essentially unchanged by the presence of 15 vol. % niobium particles embedded in the copper matrix. copyright 1996 American Institute of Physics