Surface relief effects associated with the formation of grain boundary allotriomorph in an Fe-C alloy

Journal Article · Fri May 01 04:00:00 EDT 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(97)00482-5· OSTI ID:616464

Bo, X Z; Fang, H S ^[1]

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1. Tsinghua Univ., Beijing (China). Dept. of Materials Science and Engineering

Surface relief effects associated with the formation of grain boundary allotriomorph (GBA) in an Fe-C alloy have been first studied by scanning tunneling microscopy (STM). It was discovered that the GBAs which exhibit the surface relief are only developed into one austenite grain, which means the interface between the austenite and the GBA which exhibits surface relief is partially coherent, and the interface between the austenite and the GBA nucleated at the same grain boundary but developed into the adjacent austenite grain may be incoherent. The maximum shape deformation of surface relief due to GBA precipitation is ca. 0.39, which is consistent with that of Widmanstaetten ferrite plates. Accompanying the formation of Widmanstaetten sawteeth, surface relief is produced, which is composed of reliefs associated with several sideplates. By STM the boundaries between GBAs are clear, which indicates that they are resulted from edge-to-edge (ETE) or face-to-face (FTF) sympathetic nucleation. Super ledges (ca. 300 nm high) were observed on the broad face of GBA. All these results can be rationally interpreted by the sympathetic nucleation-ledgewise growth mechanism.

• OSTI ID: 616464
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 8 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL DEFECTS
GRAIN BOUNDARIES
PRECIPITATION
STEELS
SURFACE PROPERTIES
WIDMANSTAETTEN STRUCTURE