PHYSICAL CHEMISTRY OF RECYCLING OF CAST ALUMINUM MATRIX COMPOSITES

10.25712/ASTU.1811-1416.2022.02.014

Abstract

The increase in the scale of industrial development of cast aluminum matrix composites is constrained by the insufficient elaboration of the issues of their recycling. Reducing non-returnable technological waste and identifying effective approaches to recycling waste products will help reduce the cost of manufacturing products from cast composite materials. One of the most economically attractive options for processing waste from the production and consumption of aluminum matrix composites is direct remelting for reuse in the production of castings and ingots, however, in this case, it is necessary to take into account the possibility of degradation of the reinforcing phase. In this paper, the mechanism of the occurrence of physicochemical processes of interaction between the components of cast aluminum matrix composites AK12och + 10 vol.% B₄C during their processing by direct remelting is considered. It has been experimentally shown that repeated remelting results in an increase in the proportion of the Al₃BC phase in the structure of the composites, which is a consequence of the intensification of interfacial reactions at the interfaces. The composition and quantity of the products of interaction of the aluminum melt with boron carbide will depend on the process temperature and the duration of their contact until the moment of crystallization of the aluminum matrix composite. It has been calculated that the overheating temperature of cast aluminum matrix composites with boron carbide during their recycling should not exceed 858 ºC due to a change in the thermodynamic conditions of interaction of the components, accompanied by a sharp intensification of the process of degradation of reinforcing particles.