INTERPHASE CHARACTERIZATION IN COMPOSITES WITH NEW NONDESTRUCTIVE METHODS

Results of single-fibre pull-out tests reflect a combination of adhesi ve, cohesive and frictional phenomena that complicate micromechanical modelling and the relation to composite properties. SEM images of frac ture surfaces detected cohesive fracture and unstable crack propagatio n during pull-out of well sized fibres out of both ductile and brittle matrices. New non-destructive methods have been used to characterize the physical properties of interphases. Atomic force microscopy in for ce modulation mode has visualized interphases of 1 to 3 mu m thickness and gradients depending on the fibre-matrix model composite. The sing le fibre dynamic load test has been shown to be a feasible tool for de termination of fibre-matrix adhesion or friction and ductility of matr ix. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.