Interface characteristics and mechanical properties of Al0.6CoCrFeNi/5052Al matrix composites fabricated via vacuum hot-pressing sintering and annealing

Abstract

In this study, Al0.6CoCrFeNi high-entropy alloy particle reinforced 5052Al matrix composites prepared via vacuum hot-pressing sintering were annealed. Experimental techniques such as SEM, XRD, EPMA, Vickers hardness, and uniaxial compression were used to characterize the prepared composites' microscopic morphology and mechanical properties. Furthermore, the Boltzmann-Matano diffusion theory and diffusion layer thickness curve fitting methods were used to predict the trend of the thickness of the diffusion layer under various annealing conditions. The results of this study suggest that the thickness of the diffusion layer increased parabolically with an increase in annealing temperature or annealing time. The intermetallic compounds (IMCs) generated in the diffusion layer region were Al13Co4-, Al9Co2-, and Al18Cr2Mg3-type phases. The mechanical properties of the composites were closely related to the change in the thickness of the diffusion layer: when the annealing temperature was 773 K/8 h, the compressive strength and microhardness of the composites reached the maximum values of 345.7 MPa and 82.8 HV0.2, respectively. Furthermore, the linear fitting method with the addition of the incubation period provided the best fit to the experimental values and provided a reference for subsequent modulation of the composite properties by varying the thickness of the diffusion layer.