中文摘要：

采用不同挤压工艺对均匀化退火后的Mg-3Al-2Sc合金进行了热挤压实验，分析了挤压态Mg-3Al-2Sc合金显微组织及力学性能的变化。结果表明：在挤压温度380℃、挤压速度50mm／min下，挤压态Mg-3Al-2Sc合金可获得均匀的再结晶组织和良好的力学性能。挤压温度降低至350℃，强度明显提高，塑性降低，但挤压速度提高至70mm／min，强度和塑性都降低。并且，经350℃、50mm／min工艺挤压后，Mg-3Al-2Sc合金的拉伸断裂为沿晶断裂与准解理断裂的混合断裂，提高挤压温度可显著降低合金的沿晶断裂倾向。

英文摘要：

The hot extrusion experiments for the Mg-3Al-2Sc alloy after homogenizing annealing treatment with different extrusion processes were carried out, while the microstructure and the mechanical properties of as-extruded Mg-3Al-2Sc alloy were analyzed. The results show that the homogeneous recrystallization microstructure and good mechanical properties in the as-extruded Mg-3Al-2Sc alloy were acquired at the extrusion temperature of 380~C and the extrusion speed of 50 mm/min. When the extrusion temperature is 350~C, the strength of alloy obviously increases and plasticity of alloy decreases. However, when the extrusion speed rises up to 70 mm/min, both strength and plasticity of the alloy decrease. Furthermore, under the extrusion process of 3500C and 50 mm/min, the fracture mechanism of the extruded Mg-3AI-2Sc alloy is mixed-mode with intergranular fracture and quasi-cleavage fracture, and raising extrusion temperature can singnificatly reduce tendency of intergranular fracture in the Mg-3Al-2Sc alloy.