POROSITY-DEPENDENCE OF ULTRASONIC VELOCITY IN SINTERED MATERIALS - A MODEL-BASED ON THE SELF-CONSISTENT SPHEROIDAL INCLUSION THEORY

The porosity dependence of ultrasonic velocity in porous sintered mate rials has been modelled using the self-consistent spheroidal inclusion theory. Considering the pores to be oblate spheroids, an effective as pect ratio has been determined from experimental data, which serves as an additional parameter to describe the observed variation in ultraso nic velocity with porosity. With the exception of two cases in the ten investigated, this single parameter describes satisfactorily the vari ation of both longitudinal ultrasonic velocity and transverse ultrason ic velocity with volume fraction of pores.