The concept of a tri-modal composite brings together the two materials design strategies of metal matrix composites and bi-modal microstructures. These materials consist of three primary microconstituents: ultrafine grain matrix, coarse grain matrix and hard ceramic particle reinforcement. Because these materials are fabricated through the application of cryomilling and thermo-mechanical consolidation techniques, they also contain finely dispersed oxides and nitrides, plus a substantial volume fraction of interfaces and grain boundaries. These materials allow us to enhance performance through controlled microstructural design and to study fundamental phenomena that control behavior. In this presentation, I will review the key performance characteristics exhibited by these materials, including extremely high strength for an aluminum-based material ( >1000 MPa) and extreme thermal stability (at temperatures up to ninety-seven percent of the absolute melting point), as well as distinct microstructural features and mechanisms that control strength, ductility, toughness and wear resistance.