Effect of area fraction and morphology of silicon particles on fracture behaviour of hypoeutectic Al-Si alloys under resonant vibration

The effect of area fraction and morphology of silicon particles on the fracture behaviour of hypoeutectic Al-Si alloys was studied under resonant vibration. Experimental results suggested that vibrational life of specimens was affected by deflection amplitude which could be correlated with area fraction of silicon particles, and by morphology of silicon particles. Increasing the area fraction of silicon particles can increase a specimen's damping capacity, which may reduce the deflection amplitude of the specimen. A reduction of deflection amplitude could be considered as a factor which increases vibrational life. In as-cast samples, acicular silicon particles were detrimental to the vibrational life across a range of silicon contents, and consequently, the factor of deflection amplitude did not cause a significant effect. However, after spheroidizing the silicon particles by solution treatment, the damping indicated by the effect of deflection amplitude became influential and the vibrational life could be improved by increasing the area fraction of silicon particles.