Effect of heat treatment on the interface of high-entropy alloy particles reinforced aluminum matrix composites

In this paper, high entropy alloy particles reinforced 5052 aluminum matrix composites were successfully prepared by vacuum hot pressing sintering technology. Interface layers with different thickness were formed in the composites by heat treatment. The effects of heat treatment temperature and time on the interface layer of composites were systematically studied by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), X-ray diffraction (XRD), electron probe microanalysis (EPMA) and nano-indentation. The results show that the new core-shell structure particles are dominant in the composites with long holding time at 500 °C heat treatment. Hardness and Young's modulus of the composites are obviously improved by the generation of the interface layer. With the increase of heat treatment time, the thickness of the interface layer increases, and the discontinuous interface layer will obviously increase the hardness and Young's modulus of the composites, which is related to the stress concentration and the bonding degree between the interface and the matrix.