Microstructure and mechanical behaviour of a SiC particles reinforced Al-5Cu composite under dynamic loading

The mechanical behaviour of a composite of Al-5Cu matrix reinforced with 15 % SiC particles was studied at different strain rates from 1 x10(-3) to 2.5 x10(3) s(-1) using both a conventional universal testing machine (for low s train-rate tests) and a split Hopkinson bar (for tests at dynamic strain ra tes), Whilst the yield stress of the composite increases as the strain rate increases, the maximum flow stresses, 440 MPa for compression and 450 MPa for tension, are independent of strain rate. The microstructures and defect structures of the deformed composite were studied with bath scanning elect ron microscopy and transmission electron microscopy and were correlated to the observed mechanical behaviour. Fracture surface studies of samples afte r dynamic tensile testing indicates that failure of the composite is contro lled by ductile failure of the aluminium matrix by the nucleation, growth a nd coalescence of voids. (C) 1999 Elsevier Science S.A. All rights reserved .