Pull-out tests with fibre-metal systems

Abstract

Fibre pull-out experiments have been carried out to compare the behaviour of reactive and non-reactive fibre-reinforced metal systems. The test samples were made by melting the metal matrix in vacuum and lowering the fibre a known depth into the liquid. In all cases some brittleness appeared to develop, since final interface failure, except with steel-99% AI, was sudden, and the values of the debonding force were quite scattered in all cases. Otherwise the results agreed with earlier observations, i.e. a linear increase in debonding force with increasing embedded length until the force was high enough to break the fibre rather than debond it. Some yielding was noticeable before failure. An elasticity analysis suggested that high shear stresses were needed in some cases to initiate yielding. However, the interface strengths, as indicated by the debonding forces, were no more than about twice the shear yield stresses of the matrices, as indicated by compressive tests on the metals. A reaction layer was obse...