The Effect of Pre-compaction on Properties of Mg/SiC Nanocomposites Compacted at High Strain Rates

Abstract

The effect of pre-compaction on mechanical properties of Mg/SiC nanocomposites prepared through dynamic compaction was investigated. The dynamic compactions were carried out at two different loading rates using Drop Hammer (DH) and Split Hopkinson Bar (SHB). The quasi-static pre-compaction was performed under two different pressures of 50 and 100MPa and at 450◦C. The results show that the highest improvement in density, hardeness, and strength are obtained for the pre-compaction pressure of 50MPa. The reason is believed to be due to the discharge of the air packets trapped between the particles. For the pre-compaction pressure of 100MPa, however, density, strength, and hardness decrease. The reason is thought to be due to creation of cracks and faults in the specimens. The results indicate that there is an optimum for the pre-compaction pressure which varies depending on the type of matrix, reinforcing particles, and compaction loading rate.