Superalloy 718 and Derivatives: Environmental Behavior & Protection I
Program Organizers: Joel Andersson, University West; Chantal Sudbrack, National Energy Technology Laboratory; Eric Ott, GE Additive; Zhongnan Bi, Central Iron and Steel Research Institute

Monday 1:00 PM
May 15, 2023
Room: Admiral
Location: Sheraton Pittsburgh Hotel at Station Square

Session Chair: Eric Ott, GE Additive; Ian Dempster, Wyman Gordon /PPC

1:00 PM Introductory Comments

1:05 PM  Invited
Compatibility of Wrought Superalloys with Supercritical CO₂: Bruce Pint¹; ¹Oak Ridge National Laboratory
    Supercritical CO₂ (sCO₂) power cycles, particularly direct-fired cycles, have the possibility of revolutionizing clean fossil energy. To maximize efficiency, the peak temperatures are expected to be above 700°C and, therefore, require the use of wrought superalloys for structural components. For the highest temperature applications >750°C, precipitation strengthened alloys such as 740 and 282 have been shown to have good compatibility in sCO₂ without impurities (i.e. indirect cycles). At temperatures <650°C, it would be desirable to use less expensive alloys, however, steels are known to be susceptible to carburization, especially with O₂ and H₂O impurities in 300 bar sCO₂. Laboratory autoclave results with and without O₂ and H₂O impurities typical of direct-fired cycles are being collected on a range of alloys including less expensive Ni-based alloys like 825 and 120 and advanced austenitic steels like 709. Their relative performance is being compared after 1-2 kh exposures at 600°-800°C and reaction products are being characterized using a variety of characterization techniques to study the reaction products and quantify the C content. Research sponsored by the U.S. Department of Energy, Office of Fossil Energy and Carbon Management.

1:35 PM
Long Term Thermal Stability and Oxidation Resistance of HAYNES 233 Alloy: Lee Pike¹; Bingtao Li¹; ¹Haynes International Inc
    HAYNESŽ 233™ alloy was recently developed to provide the market with a readily fabricable alloy combining the properties of high creep strength and excellent oxidation resistance to temperatures of 2000°F (1093°C) and above. This combination of properties is desirable for a number of high temperature applications, including hot gas components in aerospace and industrial gas turbines, industrial heating fixtures and sensors, and various structural components in the emerging technology market. The development and key features of 233 alloy have been detailed elsewhere [L.M. Pike et al., Journal of Materials Engineering and Performance, Vol. 28 (4), 2019, pp. 1929-1935].