Mechanical vibration-assisted metal powder filling process and mechanism based on the discrete element method

In this study, the discrete element method was combined with physical experiments to examine the capsule filling practice in the hot-isostatic-pressing process and to study the densification of spherical particles in a three-way pipe capsule for offshore engineering under mechanical vibration conditions. The effects of vibration parameters—such as the vibration time, vibration frequency, vibration amplitude, rolling friction coefficient, sliding friction coefficient, recovery coefficient, and other particle properties—on the filling density were analyzed. The results showed that the packing density in the three-way capsule could be increased considerably using a vibration frequency of 40 Hz and a vibration amplitude of 2.5 mm. The contact form between particles in the vibration-assisted mold-filling process was determined and the particle velocity field, compression force, and coordination number under a single harmonic vibration period were analyzed. The real-time motion of the particles at the micro level was visualized, and the mechanism of the mechanical vibration effect on mold filling and densification was explored. The distribution and evolution of the coordination number indicated that the distribution of the filling density was uneven, and that the change in the coordination number of particles at the bottom exhibited no major response to the vibration.