The effect of prior austenite grain size on hierarchical structures of lath martensite in a 22MnB5 steel
Journal
Materials Science and Engineering: A
Journal Volume
951
Start Page
149544
ISSN
09215093
Date Issued
2026-01
Author(s)
Tseng, Chien-Yu
Cheng, Ming-Yi
Tsao, Tzu-Ching
Chiu, Po-Han
Chen, Yu-An
Chen, Chu-Jen
Misra, R.D.K.
Yang, Yo-Lun
Chen, Chih-Yuan
Yang, Jer-Ren
Abstract
Electron backscatter diffraction (EBSD) has been extensively employed to characterize the lath martensite structure; however, systematic investigations of substructures across entire prior-austenite grains, particularly the spatial distributions of lath sub-units observed along specific zone axes, remain limited. In this study, samples of 22MnB5 steel (Fe-0.22C-1.17Mn-0.17Si-0.25Cr-0.0021B, wt%) were subjected to austenitization at 1000 °C or 1200 °C for 5 min, followed by rapid quenching to room temperature. The treatments produced small (∼8 μm, SG) and large (∼60 μm, LG) prior-austenite grains, respectively. The resulting lath martensite substructures within the full prior-austenite grains in SG and LG samples were analyzed, with emphasis on the crystallography of sub-units along three prior-austenite orientations: [001]γ, 01¯1γ and [111]γ. The hierarchical organization of lath martensite was clearly resolved in the LG sample, where 24 Kurdjumov–Sachs (K–S) variants were distinctly identified, particularly along [001]γ. The systematic comparison of SG and LG samples provides detailed insights into the hierarchical features of lath martensite across entire prior-austenite grains with specific orientations.
Subjects
Electron backscatter diffraction (EBSD)
Hierarchical structures
Inverse pole figures
Kurdjumov–Sachs (K–S) variants
Lath martensite
Pole figures
Prior-austenite grain size
Publisher
Elsevier Ltd
Type
journal article