Enhanced Particle Dispersion in Aluminum Melts Using Multi-source Ultrasonic Vibration: Simulation and Experiments

Due to severe acoustic attenuation, the effectiveness of single-source ultrasonic vibration (SUV) in dispersing reinforcement particles within Al matrix composites is limited, particularly when dealing with high weight fractions. In this study, a short-spacing multi-source ultrasonic vibration (MUV) technique, specifically quad-source ultrasonic vibration (QUV), was introduced to prepare SiC_p/A356 composites with a high weight fraction of 15wt.% SiC particles. The characteristic of acoustic streaming and the dispersion of particles were systematically investigated through numerical simulations and physical experiments. The results reveal that QUV mitigates acoustic attenuation and expands the potential cavitation region (exceeding the cavitation threshold of 1.1 MPa) compared to single-source ultrasonic vibration (SUV). The synergistic effect of multiple ultrasonic waves not only elevates cavitation intensity but also enriches the structures of acoustic streaming, significantly reducing agglomeration and improving the dispersion of SiC particles within the Al matrix. Without ultrasonic treatment, only a small proportion of SiC particles are embedded in the Al matrix, with an S_SiC/S_t ratio of merely 2.23%. However, as the number of ultrasonic sources increases, the agglomeration of SiC particles was relieved, and the resultant holes diminish. Remarkably, under QUV treatment, the holes in the composites virtually disappear, and the S_SiC/S_t ratio increases to 9.82%. Additionally, the composites exhibit superior mechanical properties, with a tensile strength of 200 MPa and an elongation of 7.0%, which are 10.5% and 38.5% higher than those achieved using SUV, respectively.