2020 Volume 106 Issue 10 Pages 751-756
We investigated the three-dimensional morphology and crystallographic characteristics of cementite in degenerate pearlite in eutectoid steel using FIB-SEM. The three-dimensional morphology of cementite in degenerate pearlite was rod-like and/or incomplete plate-like structures. Combining the three-dimensional image with EBSD measurement data revealed that cementite grows in the low index direction. In addition, we also investigated the relationship between the pearlite morphology and the deviation angle from K-S orientation relationship (K-S OR) between austenite and pearlite during phase transformation. The deviation angle from the K-S OR with austenite in the pearlite growth direction side affected the microstructural evolution. Coarse degenerate pearlite was formed when the deviation angle from K-S OR is small, and fine degenerate pearlite and lamella pearlite tended to be formed as the deviation angle increases. From these results, we concluded that the pearlite morphology including degenerate pearlite can be classified by the deviation from K-S OR with austenite.
