Evolution of microstructure and mechanical properties of Al-B4C composite after recycling

Abstract

A remelting method was used to recycle Al-15wt.% B4C composite and the microstructure and mechanical properties of the composite were investigated before and after recycling. Scanning electronic microscope (SEM) showed that some of the particle clusters present in the original composite were broken down and the distribution of B4C in the matrix was more uniform after recycling. The interface reaction was further intensified and the protection layer coated on the surface of B4C was thicker after recycling. In addition, there were more TiB2 particles which peeled off from the surface of B4C and distributed around B4C. Al3Ti phase, which was present in the original composite, disappeared after recycling, while Al3BC phase increased markedly. Tensile test and hardness test revealed that the mechanical properties were preserved well after recycling. Therefore, it is proposed that remelting method is a feasible method for Al-B4C composite recycling.