Low-cost multi-component heat-resistant magnesium alloy and preparation method of magnesium alloy

The invention provides a low-cost multi-component heat-resistant magnesium alloy and a preparation method of the magnesium alloy. The low-cost multi-component heat-resistant magnesium alloy comprises the following components in percentage by weight: 4.2-6.7% of Al, 0.5-1.2% of Zn, 0.7-0.9% of Sr, 0.2-0.8% of Ca, 1.1-1.5% of Sn, 0.8-1.3% of Sb, 0.05-0.4% of Mn, 0.2-0.6% of Bi, 0.4-0.9% of Si and the balance of Mg. According to the low-cost multi-component heat-resistant magnesium alloy, a right amount of low-cost alloy elements such as Sr, Ca, Sn, Sb, Mn, Bi and Si are introduced; the high-temperature performance of the magnesium alloy can be remarkable improved; the application range of the magnesium alloy can be expanded; the magnesium alloy is low in cost, simple in smelting and heat treatment process and uniform in microscopic structure; the mechanical performance and the heat resistance of the alloy can be remarkably improved; after the alloy is solidified and aged, the maximum room-temperature tensile strength reaches 278MPa; the maximum tensile strength at 150 DEG C reaches 236MPa; the maximum tensile strength at 200 DEG C reaches 207MPa.