Effects of Nb/Ti/V/Ta on phase precipitation and oxidation resistance at 1073 K in alumina-forming austenitic stainless steels

Journal Article · Mon Oct 15 04:00:00 EDT 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2018.07.007· OSTI ID:22805783

Wen, D. H. ^[1]; Jiang, B. B.; Chen, G. Q. ^[1]; Tang, R.; Zhang, R. Q. ^[2]; Dong, C. ^[1]; Liaw, Peter K.

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1. Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)
2. Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu 610213 (China)

Highlights: • Effects of Nb/Ti/V/Ta on phase precipitation at 1073 K in AFA alloys are studied. • The precipitation of σ-FeCr can be accelerated by the formation of B2-NiAl. • The additions of V and Ta can improve the oxidation resistance of AFA alloys. • The precipitation of σ-FeCr will deteriorate the oxidation resistance. • Good performance can be achieved by M co-alloying and an appropriate M/C ratio. - Abstract: The present work investigated the effects of strong carbide-forming elements M (M = Nb, Ti, V, Ta) on the phase precipitation and oxidation resistance at 1073 K in alumina-forming austenitic (AFA) stainless steels (Fe-20Ni-(18–23)Cr-2.5Al-2.3Mo-0.08C-Nb/Ti/V/Ta wt%). The designed alloy rods were solid-solutioned at 1523 K for 1.5 h, and then aged at 1073 K for 24 h or oxidized at 1073 K for 500 h, respectively. Besides primary MC carbides, B2-NiAl, Fe{sub 2}M, and σ-FeCr phases would be precipitated from the γ-austenitic matrix in these aged AFA alloys. Furthermore, the precipitation of σ-FeCr could be accelerated by the B2-NiAl formation, which is related to the γ stability. The formation of MC and Fe{sub 2}M can be controlled via adjusting the ratio of M/C. The oxidation resistance of these AFA alloys can be improved effectively by V and Ta addition due to the formation of compact Al{sub 2}O{sub 3} protective scales. This work will provide a new approach to obtain a good combination of creep strength and oxidation resistance through co-alloying with Nb/Ta/V and controlling the M/C ratio within 1.0–2.0 (in molar ratio) simultaneously.

• OSTI ID: 22805783
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 144; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
AUSTENITIC STEELS
CARBIDES
CORROSION RESISTANCE
INTERMETALLIC COMPOUNDS
NIOBIUM COMPOUNDS
OXIDATION
PHASE STUDIES
PRECIPITATION
SOLID SOLUTIONS
STAINLESS STEELS
TANTALUM COMPOUNDS
TITANIUM COMPOUNDS
VANADIUM COMPOUNDS