Ultrasonic techniques in evaluation of metal matrix particulate composites

Gravity- and pressure-die-cast aluminium alloy-ceramic particle composites containing dispersions of alumina and zircon particles were characterized using a pulse echo ultrasonic technique. Good agreement was obtained between the experimental and theoretical values of longitudinal ultrasonic velocities and moduli in the case of low (less than 1%) porosity composites. By suitably controlling the casting conditions to reduce porosity levels below 1%, these ultrasonic measurements can be used for rapid determination of the volume percentage of particles in a production unit. © 1990.