The quality of ultrasonically consolidated parts critically depends on the bond quality between individual metal foils. This necessitates a detailed understanding of interface microstructures and ultrasonic bond formation mechanisms. In this work, the interface microstructures of a variety of ultrasonically consolidated similar and dissimilar metal samples were investigated. Samples with embedded SiC fibers were also investigated. Based on detailed microstructural studies, the mechanisms of foil bonding and fiber embedment in ultrasonic consolidation have been discussed. © 2009 Elsevier B.V. All rights reserved.