The densification and mechanical behaviors of large-diameter polymer-bonded explosives processed by ultrasonic-assisted powder compaction

Improving the density of parts, structural homogeneity, and mechanical properties are the most challenging issues in the PBX compaction process. In this study, the ultrasonic-assisted PBX compaction technique and equipment were introduced and designed. With this equipment, it is found that the density of compacted PBX parts increases, and the diameter expansion and density differences decrease by applying ultrasonic vibration. The influences of compaction pressure, hold time and particle size on the compaction were also analyzed. The results indicate that increasing the pressure and time, while decreasing the particle size, results in a higher density and strength of PBX parts. Then, the microstructures were analyzed to show the mechanism of density distributions. It is found that the density increase is due to the particle's rearrangement leading to a dense structure and smaller particle sizes with ultrasonic vibration. Finally, the compressive modulus and strength, and the tensile fracture and strength were found to increase by applying ultrasonic vibration. These mechanical properties decrease along the radial and axial direction, indicating the surface effect of the ultrasonic vibration. CO 2021 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The study introduced an ultrasonic-assisted PBX compaction technique and equipment, leading to increased density and strength of parts. Adjusting compaction pressure, hold time, and particle size can improve the physical properties of PBX parts.