Superalloys resist hot corrosion and oxidation

Demand for lower fuel costs is driving turbine designers on all fronts to look for ways to increase firing temperatures to achieve higher operating efficiencies. Historically, hot corrosion attack has been the dominant environmental issue for industrial gas turbine engines. Now, efforts to raise firing temperatures create the need for materials that can endure exposures where both hot corrosion and oxidation predominate. Two single-crystal superalloys have been developed in response to these market demands. By providing a blend of hot corrosion and oxidation resistance, CMSX-11B and CMSX-11C alloys directly address the need for better components in turbine engines that burn fossil fuels. This article discusses alloy design and manufacture, mechanical properties, and results of hot corrosion and oxidation tests.