In this work, the static and dynamic compaction response of a six-material mixture, containing both brittle and ductile constituents, is compared. Quasi-static and dynamic compaction experiments were conducted on samples and the results compared to simulations. Optical analyses of compacted samples indicate that dynamically compacting samples to near 300 m/s is not sufficient for complete compaction or localized grain melt. Simulations indicate that a wide distribution of temperature and stress states are achieved in the dynamically compacted samples; compaction speeds should be increased to near 800 m/s at which point copper grains achieve melt temperatures on their surfaces. The experimental data is used to fit a bulk P-α equation of state (EOS) that can be used for simulating large-scale dynamic compaction for industrial applications.

Abstract. The aviation industry manufactures brake-pads from a multi-component mixture of copper, iron, silica, graphite, molybdenum-disulfide and tin. The work presented here investigates the possibility of utilizing dynamic compaction in this manufacturing process and compares the end state morphologies and damage mechanisms between samples prepared by static pressing and sintering or dynamic compaction without sintering. Statically compressed and sintered samples were obtained from a commercial vendor, whereas green samples were prepared at Marquette University in a hydraulic press up to pressures of 0.04 GPa. Dynamically compressed samples were prepared in the 25.4 mm air gun at Marquette University up to pressures of 0.5 GPa. The end state morphology of all of the samples was investigated using a scanning electron microscope and electron dispersive spectroscopy. From the dynamics experiments a bulk Hugoniot was obtained and used in a numeric investigation of the compaction process. Both bulk and mesoscale simulations were used to not only reproduce the bulk Hugoniot but also to investigate damage mechanisms. It was found that the dynamically compressed samples had large regions of sintered grains with lateral fractures resulting from release.