Published:
Springer Science and Business Media LLC, 2022
Published in:
Metallurgical and Materials Transactions A, 53 (2022) 8, Seite 3034-3043
Language:
English
DOI:
10.1007/s11661-022-06724-z
ISSN:
1073-5623;
1543-1940
Origination:
Footnote:
Description:
<jats:title>Abstract</jats:title>
<jats:p>The martensitic transformation in a high carbon steel was studied by a new experimental approach focusing on the nucleation and growth as well as the variant pairing of the early-formed martensite. A mixed microstructure with tempered early-formed martensite and fresh later-formed martensite was achieved by a heat treatment with an isothermal hold below the martensite start temperature. <jats:italic>In-situ</jats:italic> high-energy X-ray diffraction showed no further transformation of austenite to ferrite/martensite during the isothermal hold. The tempered early-formed martensite was characterized with a combination of light optical microscopy and local tetragonality determination by electron backscatter diffraction. The characterization allowed qualitative as well as quantitative analysis of the tempered early-formed martensite with regard to the prior austenite grain boundaries (PAGB) and variant pairing. The early-formed martensite was shown to grow predominantly along the PAGBs and clustering was observed indicating an autocatalytic nucleation mechanism. The variant pairing of the early-formed martensite had a stronger plate character compared to the later-formed martensite.</jats:p>