Micromechanisms of Deformation and Fracture in Aluminum Based MMCs - Interface Effects.

摘要

Microstructural effects on the deformation and fracture of Aluminum-based metal matrix composites have been determined. Microstructural variables investigated included the reinforcement size, volume fraction, and matrix microstructure. Reinforcement sizes studied included 5 um and 13 um SiC particulates at both the 15 and 20 volume percent levels. Matrix microstructures were systematically varied via heat treatment and were quantified using transmission electron microscopy. Fracture toughness was evaluated using J-integral test techniques and utilized in-situ monitoring of fracture inside a Scanning Electron Microscope. Mixed mode fracture toughness tests were also conducted. In addition to the fracture toughness tests, additional tests were conducted on specimens deformed under high pressure. The composites exhibited high ductility under pressure (e.g. ef = 80%). Laminated composites were additionally processed and exhibited significant improvements in both bend ductility and fracture toughness. Metal Matrix Composites, Toughness, Laminates, Microstructure Effects, Ductility.