Effect of Sb modification on microstructure and mechanical properties of hypoeutectic Al-11Mg2Si alloy

Effects of Sb modification on the eutectic microstructure and tensile properties of hypoeutectic Al-11Mg(2)Si alloy were systematically investigated in this work. Eutectic Mg2Si phase in hypoeutectic Al-11Mg(2)Si 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.