Low-cost microalloyed high-performance rapidly-extruded magnesium alloy and preparation method thereof

The invention provides a low-cost microalloyed high-performance fast extrusion magnesium alloy and a preparation method thereof, and belongs to the field of metal material processing, the magnesium alloy comprises the following components by mass: 0.4-2.2 wt.% of bismuth, 0.3-0.7 wt.% of manganese, 0.2-0.6 wt.% of zinc, 0.2-0.5 wt.% of aluminum, and the balance of magnesium and inevitable impurities, and the content of the inevitable impurities is less than or equal to 0.05 wt.%. The total content of alloying elements in the alloy system is less than or equal to 4wt.%, and the alloy system belongs to a low-alloy system. The preparation method of the alloy mainly comprises the following steps: casting refined magnesium alloy, and then extruding the magnesium alloy into a bar. The production cost of raw materials is saved, the long-time high-temperature heat treatment process is simplified, fine grain strengthening and second-phase strengthening can be achieved, the obtained alloy has high strength, meanwhile,