Tseng, Chien-YuChien-YuTsengCheng, Ming-YiMing-YiChengTsao, Tzu-ChingTzu-ChingTsaoChiu, Po-HanPo-HanChiuChen, Yu-AnYu-AnChenChen, Chu-JenChu-JenChenMisra, R.D.K.R.D.K.MisraYang, Yo-LunYo-LunYangTE-CHENG SUChen, Chih-YuanChih-YuanChenYang, Jer-RenJer-RenYang2026-01-152026-01-152026-0109215093https://www.scopus.com/record/display.uri?eid=2-s2.0-105024210016&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/735342Electron 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.falseElectron backscatter diffraction (EBSD)Hierarchical structuresInverse pole figuresKurdjumov–Sachs (K–S) variantsLath martensitePole figuresPrior-austenite grain sizejournal article10.1016/j.msea.2025.1495442-s2.0-105024210016