Effects of nitrogen implantation on low cycle fatigue behavior of ferritic Fe-24Cr-4Al stainless alloy

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/BF02652359· OSTI ID:382517

Zhu, S M; Tjong, S C ^[1]

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1. City Univ. of Hong Kong, Kowloon (Hong Kong). Dept. of Physics and Materials Science

The effects of nitrogen implantation on cyclic deformation response, near-surface dislocation substructure, surface slip band formation, crack initiation, and fatigue life under low cycle fatigue of the ferritic Fe-24Cr-4Al stainless alloy were investigated. Implantation was carried out at an energy of 65 keV and at a fluence of 2 {times} 10{sup 17} ions/cm{sup 2}. Nitrogen implantation resulted in a substantial cyclic hardening in the alloy. Homogeneous planar dislocation arrangements were formed in the near-surface region of implanted specimens after fatigue, while dislocation loop debris and patches were developed in the un-implanted specimens. Moreover, formation of persistent slip bands (PSBs) was greatly suppressed in the surface of the implanted specimens. Nitrogen implantation also resulted in an alteration of the crack initiation mode from the grain boundary to the surface penetration of the PSBs nucleated below the surface layer. Fatigue life improvements after nitrogen implantation could only be obtained when the PSBs were not only suppressed but also homogenized in the implanted surface layer.

• Sponsoring Organization: USDOE
• OSTI ID: 382517
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 9 Vol. 27; ISSN 1073-5623; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CHROMIUM ALLOYS
CRACK PROPAGATION
CRACKS
DISLOCATIONS
FATIGUE
GRAIN BOUNDARIES
HARDENING
ION IMPLANTATION
IRON BASE ALLOYS
NITROGEN
SERVICE LIFE
SLIP