Characterisation of anisotropic elastic constants of continuous alumina fibre reinforced aluminium matrix composite processed by medium pressure infiltration

The anisotropic elastic properties of an Al metal matrix composite unidirectionally reinforced with continuous alpha-alumina fibres fabricated, by a medium pressure infiltration technique, has been characterised using ultrasonic bulk and surface waves, tensile tests and microstructural analysis. The ultrasonic data are analysed under the continuum mechanics approximation. Elastic anisotropy is studied by varying the direction of propagation of ultrasonic waves. An optimisation process is used to recover all the volumic effective elastic moduli from bulk ultrasonic velocities. Two local (sub-surface) shear effective moduli are determined from the surface waves velocities. To discuss the elastic anisotropy of the material in relation with its microstructure and the manufacturing process, microstructural observations are correlated to the global and local ultrasonic evaluations and to the mechanical characterisation conducted in and out of symmetry axis. (C) 1999 Elsevier Science Ltd. All rights reserved.