Micromechanical Modelization of the Influence of Microstructure on the Behavior and Damage of a G_r/AL Composite

Abstract

A new solid phase coextrusion process to manufacture metal matrix composites has been developed. As part of this study, the influence of following parameters on the behavior and damage mechanisms of the composite was investigated: aspect ratio of the fibers, orientation of reinforcement and local concentration distribution. This has been achieved through an equivalent inclusion analytical approach based on a micro-macro modelization. The prediction of the elastic constants, the coefficients of thermal expansion and the yield criterion can be determined from the microstructure. The influence of the distribution of fibers on the development of local plasticity has been demonstrated. It appears that the configuration of bundles of fibers has a dramatic effect on the propagation of damage which occurs at the fiber tip. An analytical criterion for damage initiation has also been suggested. These results are compared with in situ tensile tests performed inside a scanning electron microscope, where every stages of the failure mechanism can be observed.