Compressive strength of continuous fiber reinforced aluminum matrix composites

Aluminum matrix composites can exhibit exceptionally high compressive strength (greater than or equal to 4 GPa). The main failure mechanism has been identified to be plastic kinking, although an upper bound seems to be attained when the fibers reach their compressive strength. The experimental results are consistent with a plastic kinking model in strain hardening composites. The important parameters controlling the compressive strength are the composite shear modulus, the shear yield strength, the strain hardening rate and the maximum initial fiber misorientation. Interfaces can also play an important role; composites reinforced with weakly bonded fibers have a reduced compressive strength due to their low shear strength in the fiber direction. The results can be used to design composite systems with high compressive strengths; in practice this is done by selecting matrices with high yield strengths and fast hardening rates. (C) 1997 Acta Metallurgica Inc.