Effects of ultrasonic vibration on the microstructure and tensile properties of the nano ZrB2/2024Al composites synthesized by direct melt reaction

Abstract

In this study, the effects of high-energy ultrasonic vibration on the dispersion of in situ nano-sized reinforcements were studied in nano ZrB2 particle reinforced 2024Al matrix composites synthesized from 2024Al–K2ZrF6–KBF4 system by direct melt reaction. And the microstructure of the final composites treated with different processing time of ultrasonic vibration during fabrication was examined by XRD, SEM, EDS, TEM and the tensile properties of the fabricated composites were also tested. The results show that the introduction of high-energy ultrasonic vibration in the composite melts could break up the clusters of agglomerated in situ nano ZrB2, degas the melts, significantly and results in enhancement in mechanical properties of the final composites. And the optimized processing time for the fabrication of the nano ZrB2/2024Al composites was established via the microstructure observation of the final composites to be 5 min with 1.2 kW in power and 20 kHz in frequency. Meanwhile, the mechanisms of the high-intensity ultrasonic vibration on the improvement of the in situ nanoparticle distribution and tensile properties of the composites were also discussed.