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Modulated structure of iron–carbon martensite studied by electron microscopy and diffraction
Author(s) -
Kusunoki M.,
Nagakura S.
Publication year - 1981
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889881009485
Subject(s) - martensite , cluster (spacecraft) , electron diffraction , diffraction , carbon fibers , materials science , planar , crystallography , carbon atom , atom (system on chip) , electron , electron microscope , molecular physics , chemistry , optics , microstructure , physics , composite material , computer graphics (images) , alkyl , organic chemistry , quantum mechanics , composite number , computer science , embedded system , programming language
Satellite spots appear around every fundamental spot in electron diffraction patterns of iron‐carbon martensite ( α ′) tempered in a temperature range from 273 to 363 K. High‐resolution electron microscopic observations show that they are due to the formation of a modulated structure, in which interstitial carbon atom clusters smaller than 10 Å are distributed randomly in a plane nearly parallel to (102) α ′ , with inter‐cluster distance of 10–20 Å and such carbon‐rich planar regions are spaced periodically with intervals of 10–20 Å, depending on the carbon content of the martensite. A structure analysis was made by measuring the satellite spot intensity of the electron diffraction patterns, and the displacements of atoms from their average positions in martensite were determined. The result supports the above cluster model for the modulated structure.