Development of Aluminium Foam through the Sintering Dissolution Process from the Alloy AA 3104

Abstract

The increasing demand for lightweight materials capable to absorb impact energy has driven the growth of scientific research in the metallic foams field. This paper aims to investigate the possibility to obtain Al foams from recycled aluminium alloy through the sintering dissolution process (SDP) with sodium chloride (NaCl) as space holder. Aluminium scraps from AA 3104 alloy were powdered by high energy ball milling. Alloy powder was mixed with variable weight fraction of NaCl. The mixtures were die-pressed at room temperature and then sintered at 680°C. In the following step sintered parts were immersed in boiling water to obtain the aluminium foam. Foam microstructure was characterized by scanning electron microscopy and chemical composition was analyzed by energy dispersive spectroscopy. In addition, the residual NaCl was quantified and the foam density was determined by hydrostatic method. Best result was obtained with 60 wt% of NaCl, given a relative foam density of 30%, which in turn justifies further studies with metallic foams from aluminium scraps.