Mg-Si-Sr series magnesium alloy and preparation method thereof

The invention relates to the technical field of new materials, and concretely relates to a refining of Mg2Si morphology in Mg-Si-Sr alloy by utilizing Sr, Mg-Si-Sr series magnesium alloy with improved magnesium alloy performances, and a preparation method thereof. The Mg-Si-Sr series magnesium alloy comprises the following compositions: Sr with the addition mass percentage of 3%, 6%, 9% and 12%, Si with the addition mass percentage of 4%, and the balance Mg. The preparation method comprises the following steps: (1) preparation of raw materials; (2) melting and casting of Mg-Si-Sr series magnesium alloy; and (3) compression deformation of Mg-Si-Sr series magnesium alloy. The advantages comprise that by adding the alkaline earth metal Sr in to the magnesium alloy, the morphology, the size and the distribution of Mg2Si eutectic are effectively refined, and Mg2Si is distributed in the alloy in a uniform fine dispersive way; and by adding Sr, the strength, the toughness and the heat resistance of the alloy are obviously improved, and the mechanical properties of the alloy is substantially improved.