Effect of Tempering on the Bainitic Microstructure Evolution Correlated with the Hardness in a Low-Alloy Medium-Carbon Steel
Journal article, 2020

A low-alloy medium-carbon bainitic steel was isothermally tempered at 300 degrees C for up to 24 hours which led to a significant hardness decrease. In order to explain the decreasing hardness, extensive microstructural characterization using scanning and transmission electron microscopy, X-ray diffraction, and atom probe tomography was conducted. The experimental work was further supplemented by thermodynamic and kinetic simulations. It is found that the main underlying reason for the hardness reduction during tempering is related to dislocation annihilation, possibly also with corresponding changes in Cottrell atmospheres. On the other hand, cementite precipitate size, effective grain size of the bainite, and retained austenite fraction appear unchanged over the whole tempering cycle.


Adam Stahlkrantz


Royal Institute of Technology (KTH)

Peter Hedstrom

Royal Institute of Technology (KTH)

Niklas Sarius


Hans-Ake Sundberg


Soren Kahl


Mattias Thuvander

Chalmers, Physics, Microstructure Physics

Annika Borgenstam

Royal Institute of Technology (KTH)

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

1073-5623 (ISSN)

Vol. 51 12 6470-6481

Subject Categories

Inorganic Chemistry

Materials Chemistry

Metallurgy and Metallic Materials


Chalmers Materials Analysis Laboratory

Areas of Advance

Materials Science



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Latest update

1/5/2021 7