THE POTENTIAL FOR CMCS TO REPLACE SUPERALLOYS IN ENGINE EXHAUST DUCTS

The Materials Systems Laboratory at the Massachusetts Institute of Tec hnology has conducted research to develop decision tools that can faci litate materials selection and provide a deeper understanding of the d esign tradeoffs that occur when choosing among advanced aerospace mate rials for high-temperature applications. As an illustration of the use of these tools, this paper describes research done to evaluate the ma terial alternatives currently under consideration for exhaust ducts in aircraft gas turbine engines. Although nickel-based superalloys curre ntly prevail for this application, the increasing temperatures of mode rn engines are necessitating the usage of higher temperature materials .