Filling of surface pores of aluminum foam with polyamide by selective laser melting for improvement in mechanical properties

To improve mechanical properties of porous structured materials, selective laser melting (SLM) was used to fill the surface pores of a commercial closed-cell type aluminum foam with polyamide 12 (nylon 12). It was found that polyamide powder was continuously melted and solidified under laser irradiation at an average energy density of 10 J/mm2. The mechanical properties of the aluminum foam with fabricated polyamide surface layer (composite sandwich structure) was investigated using a uniaxial compression test. The specific compressive strength of the foam with surface layer increased 2.5 times in maximum higher than that of the foam without surface layer. The improvement was not only due to the high specific strength of the polyamide but also due to the formation of the sandwich structure.