Effects of antimony on eutectic silicon and fracture mode of A357 alloy at different cooling rates.

The effects of antimony on eutectic silicon and fracture mode of A357 alloy were investigated at slow and fast cooling rates by scanning electron microscopy, transmission electron microscopy, polarizing microscope, differential scanning calorimetry, optical microscope and tensile testing. The slow cooling rate is 0.16 °C/s, and the fast cooling rate is 3.20 °C/s. The results show that with antimony addition, the eutectic silicon of A357 alloy is modified. Antimony does not modify eutectic silicon of A357 alloy by increasing the number of twins. Under the same cooling rate condition, with antimony addition, the volume fraction of eutectic phases increases, and when studying the modification of eutectic silicon of some modifiers, we also need to study the eutectic phases including eutectic silicon and eutectic α‐aluminum. With antimony addition, tensile strength and elongation of A357 alloy increase, especially under fast cooling rate conditions. With the increase of elongation, the fracture mode of A357 alloy changes from I to I+II to I+II+III. [ABSTRACT FROM AUTHOR]