Effect of reinforcement on cyclic stress response of a particulate SiC/Al composite

The cyclic stress response of SiC particulate-reinforced pure aluminium and its unreinforced matrix material, in the as-extruded condition, was investigated utilizing plastic strain-controlled testing at room temperature. The unreinforced aluminium exhibited initial cyclic hardening, cyclic stability and secondary hardening, while the composite showed gradual softening over most of the fatigue life. Transmission election microscopy examination has been made of the dislocation substructure developed during cyclic deformation. The differences in the dislocation substructure obtained from processing and its developments under cyclic strain loading were considered to give rise to the observed phenomena. (C) 1999 Elsevier Science B.V. All rights reserved.