High-strength/toughness aluminum alloy brake drum and preparation method thereof

The invention discloses a high-strength/toughness aluminum alloy brake drum which comprises the following components in percentage by weight: 31-35% of Si, 5-6% of Cu, 1-3% of Mg, 0.5-1% of Ti, 0.9-1.2% of Mn, 5-8% of Ni, 0.1-0.2% of S, 0.5-2% of RE, 0.05-0.1% of C and the balance of aluminum. The preparation method of the high-strength/toughness aluminum alloy brake drum comprises the following steps: (1) proportioning; (2) smelting; (3) modification refinement treatment; (4) extrusion casting; (5) shock cooling treatment; (6) T6 heat treatment; and (7) machining to obtain the brake drum product. By using the high-strength/toughness aluminum alloy (the silicon content is 31-35%) as the brake drum material, the brake drum has the advantages of low density, high specific strength, small thermal expansion coefficient, favorable heat stability, favorable wear resistance, favorable corrosion resistance, favorable high-temperature properties, lighter weight and the like. By using the Al-Ti-C-RE and sulfur as the modification refiners, the primary silicon and eutectic silicon can be effectively modified, thereby improving the high toughness of the material.