In-situ synthesis of Al₃BC/Al composites from amorphous boron and graphene nanoplates by solid reaction

In the present work, highly reactive amorphous B and small-size graphene nanoplates (GNPs) were used as raw materials, and in-situ synthesis of Al₃BC/Al composites by solid reaction was explored. During the solid reaction process, relative contents of AlB₂ and Al₃BC were increased linearly with the reaction temperature (from 578 to 645 °C) and reaction time (1–12 h). However, for the composites reacted at 660 °C, the Al₃BC content was slightly increased while the content of AlB₂ was decreased gradually with increase in reaction time. Regardless of the reaction temperature and time, no Al₄C₃ phase was observed in the present work. It is suggested that the Al matrix and amorphous B were initially reacted to form AlB₂, which was further reacted with C element to form Al₃BC. Although, Al₄C₃ has been widely reported in literature, AlB₂ could also be used as reactant to form Al₃BC. It has been found that the bending strength of the composites has been increased 30% (from 353 to 462 MPa) since the reinforcement was evolved from amorphous B and GNPs to Al₃BC and small content of AlB₂.