Creep of discontinuous fibre composites I. Experimental behaviour of lead-phosphor bronze

Abstract

Measurements of the creep rate of specimens of lead containing alined rods of phosphor bronze of constant length (either 4.5 cm or 2.25 cm) and diameter (0.45 mm) are described. The rate of steady-state creep has been measured for composites in which the fibres creep, and for those in which they do not, and these are compared with the rates of creep measured for the fibres and matrix alone. The deformation is very non-uniform due to small variations in volume fraction or arrangement of the wires. Voids form early in the creep test but do not immediately lead to fracture. The rate of creep is not sensitive to surface preparation of the wires. The rate of creep is compared with that predicted by a simple theory developed in paper II, which appears to be in accord with experiment.