Al/Al2O3 Metal Matrix Composites (MMCs) and Macrocomposites for Armor Applications
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
Pagination or Media Count:
Metal matrix composites MMCs combine the desirable characteristics of metals ductility and thermal conductivity and ceramics high hardness, high stiffness, low thermal expansion. In this study, AlAl2O3 MMCs with alumina particle contents ranging from 12 to 46 were fabricated by different processing approaches. Microstructures and properties density, elastic modulus, tensile strength, ductility failure strain, and thermal expansion of these MMCs were characterized. AlAl2O3 MMCs showed higher ductility than AlSiC MMCs. As the measured ductility was still less than that necessary for multi - hit armor applications, a macrocomposite concept was developed. This concept uses incorporation of high - strength, higher - CTE coefficient of thermal expansion ductile macroscopic reinforcements in the MMC to induce residual compressive stress in the MMCs with an intent of enhancing ductility. Numerical modeling on an example macrocomposite system showed that residual compressive stresses can indeed be generated. Specimens were designed to test the numerical predictions and generate data for designing a macrocomposite system. A process was developed and applied successfully to fabricate the macrocomposite specimens.
- Inorganic Chemistry
- Laminates and Composite Materials
- Metallurgy and Metallography