VISCOPLASTIC BEHAVIOR OF POROUS METALLIC MATERIALS SATURATED WITH LIQUID .1. CONSTITUTIVE-EQUATIONS

Close to their melting point, metallic alloys containing a liquid phas e can be described, in the high solid fraction range, as viscoplastic porous media saturated with liquid. In this article, a model is propos ed in the general framework of the mixture theory. A constitutive equa tion for the deformation of the rate-dependent porous solid phase is g iven which is intended to improve the classical rheological descriptio n of metallic solid-liquid mixtures, in particular, in the case of non -negligible interstitial liquid pressure. Three deformation paths are studied in the frame of this constitutive equation: shear deformation, drained hydrostatic deformation and constant volume deformation in un drained conditions. The characteristic functions appearing in the cons titutive equation will be identified, using these three deformation pa ths in the experimental part of this study. (C) 1997 Elsevier Science Ltd.