Fig. 1 EBSD results of the samples. a1-d1 Phase map, statistical results of equivalent diameters, KAM map, and statistical results of KAM values for the as-quenched sample. a2-d2 Phase map, statistical results of equivalent diameters, KAM map, and statistical results of KAM values for the solid-solution-treated sample. BCC indicates body-centered cubic iron, including ferritic and martensitic phase. FCC means face-centered cubic iron, which is austenite in this study

Fig. 2 TEM results of solid-solution-treated sample. a Orientation relationship between retained austenite and martensite, b diffraction pattern, morphology, and composition of martensite, c diffraction pattern, morphology, and composition of austenite, d diffraction pattern, morphology, and composition of ferrite. The rectangles in figure are the areas that EDS was conducted

Fig. 3 Mechanical properties of the test materials. a Engineering stress-strain curves, b working-hardening rate plots, c summary of tensile strength and total elongation [22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47], d summary of tensile strength and yield strength/tensile strength ratio [22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47]

Fig. 4 EBSD results of the solid-solution-treated steel showing in-situ tensile microstructure. FCC and BCC are face-centered cubic iron (austenite) and body-centered cubic iron (ferrite and martensite). The numerical values presented within the images denote average KAM values of FCC and BCC phases

Fig. 5 TEM results of solid-solution-treated sample after the tensile test. a and b Bright field of bandlike or blocky martensite transformed from retained austenite after the tensile test, c ferrite after the tensile test, d X-ray diffraction spectra of the different sites on the tensile specimen