A New Alumina-Forming Ni-Co-Cr Base Alloy for Service in Gas Turbine Engine Combustors and Other High-Temperature Applications

HAYNES^® 233™ alloy based on the Ni-Co-Cr-Mo-Al system has been developed for service at high temperatures. The origins of 233 alloy can be traced to a couple of Haynes alloys: 230 alloy and 214 alloy. The former is a premier high-temperature alloy with superb creep strength and is widely accepted in the gas turbine industry. It is also chromia forming. The alumina-forming 214 alloy with its 4.5% Al content possesses outstanding oxidation resistance at high temperatures, but its creep strength above ~ 1800 °F (982 °C) is very poor. The new 233 alloy attempts to bridge this performance. This paper will present preliminary test results for 233 alloy from the products of the first production heats, including the tensile and creep properties of the alloy, microstructure, oxidation properties, as well as fabricability. These results will be compared and discussed with those of popular gas turbine alloys such as 230, 214, 617, and X alloys. The preliminary test results indicate that HAYNES 233 alloy has a unique combination of excellent oxidation resistance and creep-rupture strength while at the same time being readily fabricable. These properties make the alloy an attractive candidate for a wide variety of gas turbine and other high-temperature applications.