Effect of Sb on microstructure and mechanical properties of MgzSi/Al-Si composites

The effect of Sb on the microstructure and mechanical properties of Mg2Si/Al-Si composites was investigated. The results show that Sb can improve the microstructure and mechanical properties of Mg2Si/Al-Si composites. When the content of Sb is 0.4%, the morphology of primary Mg2Si changes from dendrites to fine particles, the average size of Mg2Si particles is refined from 52 to 25 μm, and the ultimate tensile strength and elongation of the composites increase from 102.1 MPa and 0.26% to 138.6 MPa and 0.36%, respectively. The strengthening mechanism can be attributed to the fine-grain strengthening. However, excessive Sb is disadvantageous to the modification of the composites.