ALLOY DESIGN AND DEVELOPMENT OF HIGH CR CONTAINING FECRAL FERRITIC ALLOYS FOR EXTREME ENVIRONMENTS
By:
Yamamoto, Yukinori ; Pint, Bruce A; Brady, Michael P; Babu, Suresh; Kuo, Chih-Hsiang (Sean); Shassere, Benjamin
Page Number:
628-639
Book Title:
Joint EPRI – 123HiMAT International Conference on Advances in High-Temperature Materials
Publication Date:
November 9, 2023
Publisher Location:
ASM International, Materials Park, Ohio, United States of America
Conference Name:
Joint EPRI – 123HiMAT International Conference on Advances in High Temperature Materials
Conference Location:
Nagasak, Japan
Conference Sponsor:
EPRI, JSPS 123rd committee on Heat Resisting Materials and Alloys
Abstract
A new alloy design concept for creep- and corrosion-resistant, fully ferritic alloys was proposed for high-temperature structural applications in current/future fossil-fired power plants. The alloys based on Fe-30Cr-3Al (in weight percent) with minor alloying additions of Nb, W, Si, Zr and/or Y were evaluated with a design strategy for corrosion resistance though high Cr content, steam oxidation resistance through alumina-scale formation, and high-temperature creep performance through fine particle dispersion of Fe2(Nb,W)-type Laves phase in the BCC-Fe matrix, which target to be used in harsh environments such as combustion and/or steam containing atmospheres, at or above 700°C. The alloys consisted of Fe-30Cr-3Al-1Nb-6W with minor alloying additions exhibited a successful combination of oxidation/corrosion/creep-resistant performances comparable or superior to those of commercially available heat resistant austenitic stainless steels. An optimized thermo-mechanical treatment combined with selected minor alloying addition resulted in a refined grain structure with high thermal stability even at 1200°C, which improved room-temperature ductility without sacrificing the creep performance. The mechanism of grain refinement in the alloy system has been discussed.
