In general, Al-based alloys are the material candidate for structural applications where weight saving is of primary concern. However, the highest tensile strength of commercial Al-based alloys is in the range of 550~600 MPa, and usually does not exceed 700 MPa even by optimizing thermomechanical treatment or by other strengthening approaches. The technology of nanostructured materials is uniquely poised to revolutionize materials for advanced Army systems. In addition to interesting and unique physical properties, this class of novel materials exhibits a broad range of heretofore unattainable mechanical properties.Sponsor: Army Research Office, Department of Defense
The technological objectives of the research program are to develop new bulk nanostructured Al-(Mn, Cr, V)-M and Al-(V, Ti)-(Fe, Co, Ni) alloys with ultra-high room-temperature tensile strength and elevated-temperature tensile strength and new bulk nanostructured Al-Si-TM-LM alloys with good wear performance for future Army systems. The selection of these new alloy systems is based on their ability to generate nanostructured materials with high thermal stability, which enables the production of bulk nanostructured materials by existing processing approaches. With Al’s inherent low density, the ultra-high strength nanostructured Al alloys are intended for lightweight structural applications in transport vehicles, special-purpose Army vehicles (such as amphibious landing vehicles and hovercraft), protective armor components and weapon systems. High wear resistance nanostructured Al-Si alloys will be implemented in high-speed reciprocating and rotating machinery in future Army systems.
The scientific objectives of the research program are as follows: first, to establish the fundamental relationship between synthesis, nanostructure and mechanical behavior of this novel class of materials, paying particular attention to thermal stability; second, to uncover novel phenomena in the behavior of systems with scalar dimensions that fall in the nanometer scale; third, to enhance our fundamental understanding of the mechanisms that govern the deformation behavior of bulk nanostructured materials. The information obtained from these fundamental studies will allow us to establish methodologies for the large-scale fabrication of bulk nanostructured components for next-generation Army systems.