Low-cost, high-strength, cast creep-resistant alumina-forming alloys for heat-exchangers, supercritical CO2 systems and industrial applications

Patent · Tue Oct 25 04:00:00 EDT 2022

OSTI ID:1986735

Muralidharan, Govindarajan; Brady, Michael P.; Yamamoto, Yukinori

An austenitic Ni-base alloy includes, in weight percent: 2.5 to 4.75 Al; 13 to 21 Cr; 20 to 40 Fe; 2 to 5 total of at least one element selected from the group consisting of Nb and Ta; 0.25 to 4.5 Ti; 0.09 to 1.5 Si; 0 to 0.5 V; 0 to 2 Mn; 0 to 3 Cu; 0 to 2 of Mo and W; 0 to 1 of Zr and Hf; 0 to 0.15 Y; 0.01 to 0.45 C; 0.005 to 0.1 B; 0 to 0.05 P; less than 0.06 N; and balance Ni (38 to 46 Ni). The weight percent Ni is greater than the weight percent Fe. An external continuous scale comprises alumina. A stable phase FCC austenitic matrix microstructure is essentially delta-ferrite-free, and contains one or more carbides and coherent precipitates of γ′ and exhibits creep rupture life of at least 100 h at 900° C. and 50 MPa.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• Assignee: UT-Battelle LLC (Oak Ridge, TN)
• Patent Number(s): 11,479,836
• Application Number: 17/162,890
• OSTI ID: 1986735
• Country of Publication: United States
• Language: English