Anisotropic broadening of XRD peaks of α′-Fe: Williamson-Hall and Warren-Averbach analysis using full width at half maximum (FWHM) and integral breadth (IB)

Highlights: • There is a limited increase in the dislocation density in the martensite from the center to the surface of the specimen. • Both FWHM and Integral Breadth (IB) follows Conventional-WH model for undeformed material. • Significant perturbation from linearity observed for higher order peaks in deformed material • Between FWHM and IB-approach, the modified-WH model provides a better response with the FWHM-approach than IB-approach. - Abstract: The anisotropic broadening of the X-ray diffraction (XRD) peaks of shear deformed martensite (α′-Fe), using both full-width at half-maximum (FWHM) and integral breadth (IB), has been studied following conventional and modified Williamson-Hall (WH) and Warren-Averbach (WA) analysis. The crystallographic study reveals limited plastic deformation of martensite (α′) within a shallow depth from the shear surface, as indicated by marginal change in the character and density of dislocation, showing the inability of the α′-phase to accommodate the strain energy of shear deformation. More importantly, the study reveals significant perturbation of modified-WH and WA model, when IB is considered for size and strain analysis, especially for higher order peaks, whereas, FWHM shows reasonably good agreement with the above mentioned models for the range of diffraction spectrum considered.