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Formation of Widmanstätten Ferrite in a 0.036% Nb Low Carbon Steel at Temperatures Above the Ae 3
Author(s) -
Basabe Vladimir V.,
Jonas John J.,
Ghosh Chiradeep
Publication year - 2014
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201200226
Subject(s) - ferrite (magnet) , materials science , electron backscatter diffraction , microstructure , scanning electron microscope , optical microscope , coalescence (physics) , carbon steel , metallurgy , diffraction , electron microscope , composite material , optics , corrosion , physics , astrobiology
The formation of Widmanstätten ferrite was investigated in a 0.036% Nb microalloyed steel at temperatures above the Ae 3 using optical microscopy, scanning electron microscopy, and electron backscatter diffraction. Such strain‐induced ferrite appears to form in two consecutives stages: (i) stage I, first observed at strains below 0.5, leads to the presence of Widmanstätten ferrite plates only about 200 nm wide, (ii) stage II, observed at strains >0.5, involves the coalescence of the Widmanstätten plates into grains. Thus the microstructures formed by dynamic transformation are composed of fresh Widmanstätten plates (stage 1) and polygonal grains (stage 2). Over the experimental temperature range of 836–896°C, the ultrafine ferrite plates and grains have areas below 2 µm 2 and are difficult to detect using optical microscopy.