Investigation on the properties of high pressure torsion (HPT) processed Al/B4C composite

In the present work, commercially pure Al powder and Al-B4C powder mixture including 5 to 20 wt. % B4C particles, were consolidated to disc shape samples through applying high pressure torsion process at room temperature. To study the microstructural characteristics and evaluating the mechanical properties of the fabricated samples SEM, microhardness and shear punch test experiments were performed, respectively. It has been found that, by applying high compression pressure and even without applying torsion, full density can be reached in consolidation of the composites including lower than 5 wt% of B4C particles. For the samples include more reinforcement, applying torsional strain (1 to 3 turns), plus high compression pressure although has a significant effect on redistribution of B4C particles in the Al matrix, but could not lead to full density. The results also showed that microhardness values increase by increasing B4C content, only if enough torsional strain were applied. The same trend was also recorded for the maximum shear strength, so that it is justified not only by the amount of used reinforcement but also by the degree of consolidation.