3D Quantification of Particle Interaction of Compacted Powders Using Synchrotron Micro Tomography (SMT)

Abstract

Synchrotron Micro Tomography (SMT) is a powerful, non-destructive scanning technique for studying the internal structure of materials. SMT was utilized for two applications in this thesis. The first application involves tracking particle rotation of aluminum powder under different compaction strains. The experiments were conducted on two geometrical configurations by applying axial load to compact the powder in the die and acquiring SMT scans at different strain levels. The SMT scans were processed using AVIZO visualization software for further analyses. The analyses included tracking the same particle at different compaction strain levels, analyzing their volume compressibility, and then quantifying their rotational behavior with respect to the z-axis and xy plane. Particles were first tracked, colored, and then 3D volume was generated. The main findings of this analysis include: 1) the volumetric strain of the particles decreased at high compaction strain due to breakage of the particles into small fragments and elastic volumetric strain of aluminum powder; 2) initially, particles showed no rotation, followed by significant rotation, due to an increase of compaction strains; 3) the majority of the particles exhibited significant rotations near the loading plate and the curved boundary; 4) the 3D shape of the tracked particles under different compaction strains provided a significant contribution to the research area of powders by demonstrating that particles change their shape during the application of compaction. SMT was utilized to quantify sand particles position during a Cone Penetration Test (CPT) as a second application. CPT is a fast and reliable in situ method for characterizing soil properties. A CPT was conducted on a sand specimen and the scans were acquired at different penetration depths using SMT. AVIZO was used to analyze the SMT scans with an objective of identifying how the particles change their position under different penetration depths. Individual particles were tracked and colored to perform this analysis. The results of the analyses include: 1) most particles near the top of the specimen moved upward during initial penetration, due to a small overburden pressure; 2) particles belonging to the middle and bottom of the specimen showed a downward movement with CPT advancement; 3) the tracked particles provided an insight into particle interaction with advancing cone penetration.