Analytical Characterizations And First-Principles Calculations Of Dispersoids In Trimodal Aluminum Metal Matrix Composites

Trimodal aluminum (Al) metal matrix composites (MMCs) consisting of nanocrystalline Al phase, boron carbide (B4C) reinforcement particles, and coarse-grained Al phase has been successfully fabricated. These trimodal Al MMCs have exhibited extremely high dynamic compressive strength and tailorable ductility. The remarkable high strength of the MMCs have been postulated to its excellent thermal stability of the nanocrystalline Al phase as well as a variety of dispersoids that have been formed during cryomilling in nitrogen. The present work details a comprehensive analytical characterization of dispersoids in consolidated trimodal Al MMCs. Secondary ion mass spectrometry (SIMS) and analytical high-resolution transmission electron microscopy (TEM) have been utilized to determine the overall composition of nitrogen, dispersoid phase constituents, morphology, and size. Analytical and microstructural characterization results are correlated to the processing and properties of the trimodal Al MMCs. Strengthening contributions from the dispersoids and nitrogen containing Al solid solution are also explored with the First Principles calculations. © 2010 Metal Powder Industries Federation