The locally varying tetragonality in martensite grains of a high-carbon steel (1.2 mass percent C) was resolved by electron backscatter diffraction (EBSD) with a spatial resolution in the order of 100nm. Compared to spatially integrating X-ray diffraction, which yielded an average tetragonality of c/a=1.05, the EBSD measurements in the scanning electron microscope allowed to image a local variation of the lattice parameter ratio c/a in the range of 1.02 ≤ c/a ≤ 1.07. The local variation of tetragonality is confirmed by two different EBSD data analysis approaches based on the fitting of simulated to experimental EBSD patterns. The resulting EBSD-based tetragonality maps are pointing to a complex interaction of carbon concentration and local lattice distortions during the formation process of martensitic structures.
@article{arxiv.2011.10275,
title = {Tetragonality mapping of martensite in a high-carbon steel by EBSD},
author = {Gert Nolze and Aimo Winkelmann and Grzegorz Cios and Tomasz Tokarski},
journal= {arXiv preprint arXiv:2011.10275},
year = {2020}
}