The correlative use of SEM-based tools (DIC, EBSD, ECCI) in the investigation of plasticity in steels has become a widely used approach. The approach allows the determination of strain gradients and imaging of deformation structures during in-situ testing of bulk samples [1]. In particular, the ECCI technique has been established as a robust SEM technique for the imaging of crystal defects and deformation structures in single- and multi-phase steels [2, 3]. The possibility of imaging crystal defects on bulk samples has provided new insights into plasticity-based phenomena in steels such as strain localization phenomena [2] and hydrogen-related intergranular fracture behavior [3]. Accordingly, the development of SEM approaches for the imaging of crystal defects is in high demand as it has a relevant application in Steel Science. In this presentation, we introduce several approaches based on electron channeling contrast imaging (ECCI) and transmission forescattered electron imaging (t-FSEI) for the imaging of dislocations and stacking faults with optimum contrast in steels. An ECCI approach based on the g.R analysis of ECC images of a stacking fault structure by g-reversion experiments will be introduced [4]. Details of the microscope settings (set-up configuration) are discussed as well as their influence on the dislocation contrast (channeling effects). In particular, the dislocation contrast behavior imaged in (BF) t-FSEI and ECCI under the same tilting conditions is analyzed. 

References

[1] I. Gutierrez-Urrutia et al.; STAM, 2018, 19, 475-483

[2] I. Gutierrez-Urrutia et al.; Acta Materialia, 2022, 233, 118053

[3] A. Shibata et al.; Materials Science & Engineering A, 2022, 831, 142288

[4] I. Gutierrez-Urrutia; Microscopy & Microanalysis, 2021, 27, 318-325