Microstructure and corrosion behaviour of Al-Si alloy treated by high intensity ultrasonic vibrations

摘要

The effect of ultrasonic liquid metal treatment on the microstructure and the corrosion behaviour of the A356 Al-Si alloy was studied. The microstruc-tures of the Al-Si were observed by means of optical and scanning electron microscopes. The corrosion behaviour was studied electrochemically and by gravimetric method. The results showed that the microstructure was modified from a coarse acicular plate-like form when no ultrasonic vibration was used, to a finely dispersed rosette-like form when ultrasonic treatment was employed. The ultrasonically treated samples showed higher resistance to pitting than the untreated sample. The soaking process negatively affected the pitting resistance.