Interpretation of Particle Breakage under Compression Using X-ray Computed Tomography and Digital Image Correlation

Milling is a common unit operation in industry to achieve a desired particle size distribution. Particle breakage in a milling operation is related to the mechanical properties of particle and to the loading events that prevail in the mill. Despite many studies to investigate the breakage mechanism of particles during milling, establishing the grindability of a material in a milling operation remains challenging. The aim of this paper is to provide a better understanding of damage accumulation and breakage mechanism that lead to breakage of particles from the micro-scale events. In this study, a compressive test of single particle coupled with in-situ X-ray computed microtomography (μCT) was carried out. To characterize the damage accumulation of particle under different stages of compressive loading, two methods were employed. The first was to visualize 3D data by stacking scanned slices and then segmenting the 3D object into different phases using the image processing software Avizo FireTM. The second was to measure relative movement between consecutive slices by means of digital image correlation (DIC). The 3D crack representations are evaluated using the two methods and compared. The evolution of inherent crack which gives rise to damage accumulation leading to ultimate breakage of the particle is visualized and quantified. The results show that the combination of XCT with DIC provides an improved method to study the breakage mechanism of individual particle under compression.