Micromechanics of stress corrosion cracking of single-crystal austenitic type 321 stainless steel under Mode II loading

Journal Article · Sun Dec 01 04:00:00 EST 1996 · Corrosion

DOI:https://doi.org/10.5006/1.3292086· OSTI ID:417892

Qiao, L J; Mao, X ^[1]; Luo, J L ^[2]

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1. Univ. of Calgary, Alberta (Canada). Dept. of Mechanical Engineering
2. Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical and Materials Engineering

Stress corrosion cracking (SCC) of single-crystal type 321 (UNS S32100) stainless steel (SS) was investigated in 42% boiling magnesium chloride (MgCl{sub 2}) solution. Tests were performed under Mode 2 loading to study the SCC mechanism. Maximum normal stress and maximum shear stress were located at different positions on the notch surface in the Mode 2 notch specimens. Results showed SCC initiated at the maximum normal stress position. No SCC occurred at the maximum shear stress position. SCC initiated on the (111) plane and propagated on the normal stress plane. Slip bands appeared around the maximum normal stress position but not in the area around the main crack. Many microcracks {approximately} 2 {micro}m long were observed on the slip bands. Their direction was inclined {approximately} 35{degree} to the slip bands instead of along them. Nucleation resulted from interaction of dislocation pileup stress and local anodic dissolution. Multiple microcrack-nucleations increased stress around crack tips of the main and microcracks. Highly concentrated local stress from dislocation pileups increased the anodic dissolution rate locally.

• Sponsoring Organization: USDOE
• OSTI ID: 417892
• Journal Information: Corrosion, Journal Name: Corrosion Journal Issue: 12 Vol. 52; ISSN 0010-9312; ISSN CORRAK
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACK PROPAGATION
DISLOCATIONS
DISSOLUTION
EXPERIMENTAL DATA
FRACTURE PROPERTIES
MAGNESIUM CHLORIDES
NOTCHES
STAINLESS STEEL-321
STRESS CORROSION
STRESSES