Compressive behavior of porous materials fabricated by laser melting deposition using AlSi12 powder and foaming agent

Abstract

This study investigates the fabrication of porous aluminum materials with closed-cell structure using direct energy deposition. Aluminum powders mixed with foaming agent (ZrH2) is sprayed onto an aluminum substrate and subsequently fused with the substrate using a high-power laser beam. The H2 gas decomposed from ZrH2 at high temperature is trapped in the melting pool. The melting pool solidifies rapidly, and then pores are formed within the deposited material. This study investigated pore characteristics according to important parameters of the foam-deposition process, namely laser power, scanning speed, and foaming agent ratio. Experimental results show that the porosity can be controlled by adjusting the process parameters. Porous materials thus fabricated had a closed-cell structure with a maximum porosity of 24.83%. In particular, the porosity can be easily controlled by the foaming agent ratios. In the case where the foaming agent and energy were excessively supplied, the number of pores generated was low. A compression test was also conducted for fabricated specimens by varying the process parameters. Results indicate that the porous materials fabricated in this study had excellent energy absorption capability, similar to that of typical porous materials. Finally, the Young’s modulus, compressive strength, and densification performance of specimens were quantitatively compared and analyzed.