The morphology and formation mechanism of pearlite in steels

Journal Article · Mon Jun 15 04:00:00 EDT 2009 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2009.01.001· OSTI ID:22066100

Kelly, P M ^[1]

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1. Division of Materials, School of Engineering, University of Queensland, St. Lucia, Queensland 4072 (Australia)

A number of morphological features of pearlite were revealed through scanning electron microscopy using deeply etched specimens. These include cementite branching, bridging, gaps, holes and curvature. The presence of cementite thin films or networks along the austenite grain boundaries in eutectoid steel and at the interface between pearlite and proeutectoid ferrite in hypoeutectoid steel is another characteristic of pearlite. Furthermore, ferrite thin films surrounding the proeutectoid cementite in hypereutectoid steels are also observed. Hence, it is considered that in hypoeutectoid steels the nucleus for pearlite is a film of cementite rather than the expected proeutectoid ferrite and, similarly, in hypereutectoid steels pearlite forms from a ferrite film rather than from proeutectoid cementite. Convergent beam Kikuchi line diffraction was used to accurately determine the orientation relationships between pearlitic constituents and parent austenite in a Hadfields steel. The results show that neither the pearlitic ferrite nor the cementite is crystallographically related to the austenite grain into which the pearlite was growing and to that into which it was not growing. In addition, a new orientation relationship between pearlitic cementite and ferrite in the Hadfield steel was also observed.

• OSTI ID: 22066100
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 6 Vol. 60; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITE
CARBON STEELS
CEMENTITE
DIFFRACTION
FERRITE
GRAIN BOUNDARIES
INTERFACES
KIKUCHI LINES
MORPHOLOGY
ORIENTATION
PEARLITE
SCANNING ELECTRON MICROSCOPY
THIN FILMS