Effect of Cr/Al contents on the 475ºC age-hardening in oxide dispersion strengthened ferritic steels. (December 2016)

• Record Type: Journal Article
• Authors: Han, Wentuo; Yabuuchi, Kiyohiro; Kimura, Akihiko; Ukai, Shigeharu; Oono, Naoko; Kaito, Takeji; Torimaru, Tadahiko; Hayashi, Shigenari
• Is Part Of: Nuclear materials and energy. Volume 9(2016)
• Page Start: 610
• Page End: 615
• Publication Date: 2016-12
• Subjects: ODS ferritic steel -- 475℃ embrittlement -- Al and Cr effects -- Cr-enriched α′ phase -- Hardness evolution; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2016.05.015
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: The 12Cr and 18Cr-ODSs have different age-hardening tendencies by increasing Al. 9 wt.% Al suppresses the age-hardening and formation of α′ phase in 18Cr-ODS steel. ODS steels possess a lower age-hardening susceptibility than non-ODS steels. Abstract: The age-hardening in oxide dispersion strengthened (ODS) ferritic steels with various additions of Cr (12, 15 and 18 wt.%) and Al (0, 5, 7 and 9 wt.%) were investigated. After 5000 h aging at 475 º C, the hardness increases in all these ODS steels, while the increased level depends on the Cr/Al contents. In 12Cr-ODS steels, the more the Al, the higher the increased hardness is. However, in 18Cr-ODS steels, higher Al addition suppresses the age-hardening. TEM observations of 18Cr-ODS steels reveal that 9Al suppresses the formation of Cr-enriched α' phase, while the 18Cr-5Al-ODS steel comprises a plenty of α′ phases. Adding Zr in ODS steels appears to increase the age-hardening. The susceptibility to age-hardening is remarkably lower in the ODS ferritic steels than in the non-ODS ferritic steel with the similar concentration of Cr.