EFFECTS OF COMPACTING PRESSURE AND SINTERING TEMPERATURE ON THE PROPERTIES OF HIGHLY POROUS PURE ALUMINUM PRODUCED WITH BORIC ACID (H₃BO₃)

Abstract

In this study, highly porous pure aluminum material with cellular structure was fabricated via powder metallurgy route using a space holding technique with the addition of boric acid powders as pore-forming agents. Boron products, namely, the boric acid, were used as novel pore-forming agents. Aluminum powders with high porosity of ~50% were successfully produced. The experiments were focused on investigating the effects of such parameters as compaction pressure and sintering temperature on the final properties of fabricated samples by determining their optimum values. Quasistatic compressive behaviors of the obtained highly porous materials were examined at a strain rate of 10⁻³ s⁻¹. The results show that the most suitable compressive properties of the highly porous states were obtained for the samples cold-pressed under 630 MPa and sintered at 620 °C for 3 hours. According to the stress-strain behavior of the high-porous states, there is a plateau region with nearly constant flow stress and a large strain of about 70%. The densities of these high porous states were approximately 1.0 g/cm³, and the mean cell sizes amounted to about 0.6 mm. Using boric acid (H₃BO₃) powders differs from conventional processes in terms of superior comprehensive mechanical properties with static compressive strength and energy absorption of 18 MPa, and 12 MJ/m³, respectively.