title: Quantitative analysis of martensite and bainite microstructures using electron backscatter diffraction.
abstract: In the present work, ultra-high-strength steels with multiphase microstructures containing martensite and bainite were prepared by controlling the cooling rate. A new approach was proposed for quantitatively statistical phase analysis using electron backscatter diffraction (EBSD) based on the band contrast which correlates to the quality and intensity of the diffraction patterns. This approach takes advantage of the inherently greater lattice imperfections of martensite, such as dislocations and low-angle grain boundaries, relative to that of bainite. These can reduce the intensity and quality of the EBSD patterns of martensite, which decrease the band contrast. Thus, combined with morphological observations, Gaussian two-peak fitting was employed to analyze the band contrast profile and confirm the ranges of band contrast for the two phases. The volume fractions of bainite and martensite in different samples were determined successfully. In addition, the results show that increased cooling rates improve the proportion of martensite and the ratio of martensite to bainite. Microsc. Res. Tech. 79:814-819, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: The State Key Lab of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China.
authors.forename: Yongzhe
authors.initials: Y
authors.lastname: Wang
authors.affiliation: The State Key Lab of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China.
authors.forename: Jiajie
authors.initials: J
authors.lastname: Hua
authors.affiliation: Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Science, Hefei, Anhui, 230031, China.
authors.forename: Mingguang
authors.initials: M
authors.lastname: Kong
authors.affiliation: The State Key Lab of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China.|CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai, 200050, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Research and Development Center, Baoshan Iron and Steel Co Ltd, Shanghai, 201900, China.
authors.forename: Junliang
authors.initials: J
authors.lastname: Liu
authors.affiliation: The State Key Lab of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China.
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Liu
keywords: bainite; band contrast; electron backscatter diffraction; martensite; scanning electron microscopy