Effects of Sb modification on the eutectic microstructure and tensile properties of hypoeutectic Al–11Mg₂Si alloy were systematically investigated in this work. Eutectic Mg₂Si phase in hypoeutectic Al–11Mg₂Si alloy was successfully refined from the long rod-like structure into fine spherical morphology when introducing 0.2 wt% Sb, whereas 1.0 wt% Sb reversely led to the formation of coarse eutectic Mg₂Si phase. Specifically, the elongation to failure in the 0.2 wt% Sb modified alloy was significantly improved to 9.7% as compared to the unmodified counterpart (1.5%), and the ultimate tensile strength increased from 183 MPa to 208 MPa. This result can be attributed to the spheroidization of eutectic Mg₂Si phase with Sb modification, which greatly relieved the stress concentration and restrained the crack source from initiating and propagating. The achieved results could shed new light on a more efficient and economical way to obtain high-performance hypoeutectic Al–Mg₂Si alloys.

在这项工作中，系统地研究了Sb改性对亚共晶Al-11Mg ₂ Si合金的共晶组织和拉伸性能的影响。当引入0.2 wt％Sb时，亚共晶Al–11Mg ₂ Si合金中的共晶Mg ₂ Si相从长棒状结构成功地细化为细球形，而1.0 wt％Sb则相反地导致了粗共晶Mg ₂ Si的形成相。具体地，与未改性的对应物（1.5％）相比，在0.2wt％的Sb改性合金中的断裂伸长率显着提高到9.7％，并且极限拉伸强度从183MPa增加到208MPa。此结果可归因于共晶Mg ₂的球化具有Sb改性的Si相，极大地减轻了应力集中并抑制了裂纹源的萌生和扩展。获得的结果可能会为更高效，更经济的方法获得高性能的亚共晶Al–Mg ₂ Si合金提供新的思路。