A UNIFIED APPROACH FROM ELASTICITY TO VISCOELASTICITY TO VISCOPLASTICITY OF PARTICLE-REINFORCED SOLIDS

This paper presents a novel approach to determine the overall elastic- viscoplastic behavior of a particle-reinforced metal-matrix composite. It is built upon the linkage from elasticity to viscoelasticity throu gh the correspondence principle, and then from viscoelasticity to visc oplasticity by means of the concept of secant viscosity and an energy approach. Albeit approximate, this theory is analytically tractable, a nd capable of delivering the stress-strain relations of the composite system under various applied strain rates. The theory embodies the non linear, rate-dependent, and work-hardening nature of the constitutive equations of the ductile matrix, as well as the elasticity of both mat rix and inclusions. The influence of particle concentration, elastic s tiffness, and applied strain rate on the overall dilatational and devi atoric stress-strain behaviors are examined in detail. The theory is f inally applied to predict the response of a silicon-carbide/aluminum s ystem and the result is found to be in accord with experimental observ ations. (C) 1998 Elsevier Science Ltd. All rights reserved.