Structural changes in iron powder during ball milling

Abstract

X-ray diffraction line profile analysis is a powerful and convenient method to investigate the microstructural characteristics of plastically deformed materials. The selection of a suitable and reliable analysis method is critical to derive correct microstructural/material property values. Different techniques of the X-ray peak profile analysis have been used to study the microstructural parameters of ball milled iron powders viz., coherent domain size, dislocation density and nature of dislocations. The classical and modified Williamson-Hall technique and momentum method are used to derive microstructural information. The stored energy estimates were obtained using differential scanning calorimetry while the morphological details are studied with a scanning electron microscope. The domain size decreases to about 270 nm and dislocation density increases to 3.6 × 10¹⁵ m^-2 after 20 h of milling. SEM results supplements the XRD results. Stored energy of deformation also increases to 171 J/g after 20 h of milling.