Comparative Study to the Effect of Squeeze Casting and Mold Vibration on Fatigue Performance of Al-17%Si Alloy

Hypereutectic aluminum-silicon alloys have a wide acceptance in engineering application. The principal requirement for the application of these alloys are high fatigue resistance and high tensile properties. In this work an experimental comparison based on the fatigue strength, tensile strength, hardness and microstructure was carried out between Al-17%Si samples prepared by gravity die casting, squeeze casting, and casting with mold vibration. Cylindrical samples of 20 mm diameter and 150mm height were cast. Squeeze casting was achieved using a squeezing pressure of 95MPa. Mechanical vibration with a frequency of 25 Hz and an amplitude of 0.5mm was used. The results showed that due to the mold vibration the grain size was reduced by 21%, while hardness and tensile strength increased by (22%) and (40%) respectively. An improvement of 26% to 49 % in fatigue life was recorded for specimens tested with a stress amplitude of 20 to 100MPa. The grain size of samples prepared by squeeze casting decreased by 8% only, while its hardness and tensile strength increased by 18% and 36% respectively. An improvement of 18 % to 36% in fatigue life was recorded for specimens tested with a stress amplitude of 20 to 100MPa.