SBIR Phase I: Novel low temperature, in-situ processing route for high performance, light weight structural materials

This Small Business Innovation Research Phase I project relates to the use of nano-structured chemicals in the processing of light-weight magnesium (Mg) alloys for high performance applications. It is postulated that reactive nano-structured chemicals such as polyhedral oligomeric silsesquioxane (POSS) with multiple silanol functionalities will be added to Mg alloys by solid phase mixing and in-situ reaction to achieve microstructure stability at higher temperatures leading to a significant performance enhancement for Mg alloys. This in-situ processing route is achieved through creating an environment where surface metal ions, with oxides removed and positively charged by acid or flux, bond to Si-OH groups in POSS. The end reaction results in chemical attachment of high concentrations of nanoscale Si-O cage compounds that are chemically and thermally stable near the grain boundary. These nanoscale cage compounds provide obstacles to prevent overgrowth of intermetallic compounds (IMC) and retard the motions between grains at high temperatures for microstructure stability of Mg alloys. The in-situ process overcomes the common problem of dispersing nanoparticles in a metal matrix where agglomeration and clustering of nanoparticles can occur. The resulting Mg alloys will be demonstrated to have improved service and mechanical properties at both ambient and elevated temperatures. The broader impact/commercial potential of this project will be to significantly improve performance of structural Mg components enabling widespread application in the automotive and aerospace industries. The automotive and aerospace industries are under ever-increasing pressure to reduce both fuel consumption and harmful emissions. Reducing the overall weight of vehicles and aircraft is key to achieving these goals and magnesium alloys, with their low density, can often be a viable proposition. However, the widespread use of magnesium is limited by its relatively poor mechanical and high-temperature creep properties. The project goal is to produce high-strength, creep-resistant magnesium material suitable for structural applications by POSS processing. Material with high concentrations of nanoscale Si-O cage compounds will be used as a master alloy in casting operations to produce large net shaped components. The manufacturing technology developed will provide a cost advantage over foreign competition for manufacturers of structural automotive and aerospace parts.