Influence of the localized initial plastic deformation on the effective thermomechanical response of metal-matrix composites

A generalized Eshelby model, allowing interaction among reinforcing particl es under a Mori-Tanaka-like scheme, is presented. Different inclusion aspec t ratios are studied in the elastic and incipient elastoplastic regime for a model SiC-Al composite. The solution of the field equations is obtained v ia an explicit algorithm that yields the interaction field in terms of the stress and strain variables. The particles and fibers are taken as purely e lastic, and the matrix is regarded as elastic-perfectly plastic. Coefficien ts of thermal expansion (CTE) are calculated both under the assumption of p urely elastic response and at the onset of plastic localized deformation. T he simulated stress strain curves show the influence of interaction stresse s on macroscopic yield stress for different inclusion aspect ratios, with n o consideration of matrix hardening. The model allows a good simulation of the thermomechanical behavior of composite materials and contributes to the understanding of the elastoplastic transition in stress-strain curves. It can also simply explain some of the most distinctive features of the mechan ical behavior of composites. The model presents the possibility of controll ing many input variables and geometries and simultaneously considering thre e-dimensional deformation of interacting inclusion-reinforced materials wit h low computational effort. Comparisons to experimental CTE and residual st resses are provided.