Abstract
•Mg-Gd master alloy has a significant modification effect on eutectic silicon of Al-Si alloy.•The mechanism of modification of eutectic Si by Mg-Gd master alloy is twin groove mechanism.•The 1.0wt.%Mg-Gd master alloy can improve the mechanical properties of Al-Si alloy.
In this study, the modification of eutectic Si was carried out by adding Mg-Gd master alloy to Al-10Si aluminum alloy. The influence mechanism of Mg-Gd master alloy modification Si on the morphology, size and mechanical properties were studied. The results show that the Mg-Gd master alloy has a remarkable modification effect on eutectic Si, with the average length of eutectic silicon changing from 11.71 μm to 1.95 μm. A large number of twin bands appear in eutectic Si after modification, and the modification mechanism is mainly twin plane reentrant edges. After modification, the mechanical properties are improved significantly and the fracture mode is mainly quasi cleavage fracture.