Utilization of Al scrap for fabrication of Al(alloy)/Al₂O₃ composite material

In status quo, Al scrap melt is diluted with pure Al and adjusted its composition for reuse. We studied a method to utilize Al scrap directly for fabricating composite materials, which can be used for machine elements having resistance to abrasion. The composite material is a product of displacement reaction between molten Al scrap and SiO₂. Its microstructure consists of Al₂O₃ network and Al alloy among them. In this study, Al alloy was prepared which have a composition of Al scrap due to window frame of houses. The synthesized Al scrap are melted and reacted with SiO₂ at 1473 K to obtain the composite material. The mechanical properties of this material were compared with Al/Al₂O₃ and (Al-Fe)/Al₂O₃ composite materials fabricated using pure Al, and Al-Fe alloy, respectively. It was demonstrated that the composite materials using scrap had a little higher strength and hardness than Al/Al₂O₃, and they were not broken into pieces upon fracture, as occurred in the case of (Al-10 at%Fe)/Al₂O₃. Further studies needed for application of this method was discussed. It was pointed out that the reactivity and the property change with compositional fluctuations of the scraps and reduction of the reaction temperature have to be taken into consideration.