Effects of Al and Ti on HAYNES 282 with fixed gamma prime content

Traditionally, high temperature components within coal fired power plants are manufactured from ferritic/martensitic steels. However, the proposed steam temperature in the Advanced Ultra Supercritical (A-USC) power plant is high enough (760°C) that ferritic/martensitic steels will not work due to temperature limitations of this class of materials; thus Ni-based superalloys are being considered. The life cycle requirements of such alloys are very demanding and are on the order of several hundred thousand hours. In this paper a wrought Ni-based superalloy with a fixed amount of gamma prime strengthening phase will be examined, with either low Al or low Ti contents, but still within the alloy 282 nominal chemistry specification. The effect that these changes have on the gamma prime misfit and its relevance to long-term microstructural and creep strength stability will be explored both experimentally as well as with computational thermodynamics. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.