Scanning electron microscope fractography in failure analysis of steels

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Materials Characterization

DOI:https://doi.org/10.1016/S1044-5803(96)00070-8· OSTI ID:409668

Wouters, R; Froyen, L ^[1]

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1. Katholieke Univ. Leuven (Belgium). Dept. of Metallurgy and Materials Engineering

For many failure cases, macroscopic examination of the fracture surface permits discrimination of fatigue fractures from overload fractures. For clarifying fatigue fractures, the practical significance of microfractography is limited to an investigation of the crack initiation areas. Scanning electron microscopy is successfully used in tracing local material abnormalities that act as fatigue crack initiators. The task for the scanning electron microscope, however, is much more substantial in failure analysis of overload fractures, especially for steels. By revealing specific fractographic characteristics, complemented by information about the material and the loading conditions, scanning electron microscopy provides a strong indication of the probable cause of failure. A complete dimple fracture is indicative of acceptable bulk material properties; overloading, by subdimensioning or excessive external loading, has to be verified. The presence of cleavage fracture makes the material properties questionable if external conditions causing embrittlement are absent. Intergranular brittle fracture requires verification of grain-boundary weakening conditions--a sensitized structure, whether or not combined with a local stress state or a specific environment. The role of scanning electron microscopy in failure analysis is illustrated by case histories of the aforementioned fracture types.

• OSTI ID: 409668
• Report Number(s): CONF-9505386--
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 4-5 Vol. 36; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CLEAVAGE
CORRELATIONS
CRACKS
DEFORMATION
EMBRITTLEMENT
ENVIRONMENT
FATIGUE
FRACTOGRAPHY
GRAIN BOUNDARIES
STEELS
STRESSES
SURFACES