(沈阳工业大学 材料科学与工程学院，沈阳 110870)
摘 要: 为了研究镁合金在高应变速率下的动态变形行为及失效机制，采用分离式霍布金森压杆(SHPB)装置在室温下对挤压态Mg-Gd-Y镁合金进行动态压缩实验，并利用金相和扫描电子显微镜对冲击后的试样进行显微分析，探讨了Mg-Gd-Y镁合金沿挤压方向(ED)、横向(TD)及法向(ND)的动态压缩力学性能和失效行为与塑性变形方式。结果表明：在动态压缩载荷下，挤压态Mg-Gd-Y镁合金沿ED、TD、ND 3个方向表现出连续屈服的变形特征，随应变速率的提高，具有正应变速率强化效应，动态压缩力学性能无明显的各向异性，ED方向的动态压缩性能略优于其他两个方向的；挤压态Mg-Gd-Y镁合金在动态压缩载荷下的断口形貌呈韧脆混合的准解理断裂特征，对载荷方向不敏感；挤压态Mg-Gd-Y镁合金在动态压缩载荷下的变形方式为孪生和滑移共同作用机制，并伴随动态再结晶现象。
关键字: Mg-Gd-Y镁合金；分离式Hopkinson杆；动态力学性能；失效行为
（School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China）
Abstract:In order to investigate the dynamic deformational behavior and failure mechanisms of magnesium under high strain rates, the split Hopkinson pressure bar (SHPB) was used to investigate the dynamic mechanical properties of extruded Mg-Gd-Y magnesium alloy at room temperature. The samples after compression were analyzed by scanning electron microscopy (SEM) and metallographic microscopy. The dynamic mechanical properties, crack performance and plastic deformation mechanism of extruded Mg-Gd-Y magnesium alloy along the extrusion direction (ED), transverse direction (TD) and normal direction (ND) were discussed. The results show that, the extruded Mg-Gd-Y magnesium alloy under dynamic compression along ED, TD and ND directions yields continuously, and has the positive strain rate effect when strain rates rise. The dynamic mechanical properties do not exhibit strong anisotropy and the dynamic compression properties along ED direction are the best among those of three directions. The fracture performance of extruded Mg-Gd-Y magnesium alloy along different directions is mix-fractured quasi-cleavage fracture and is not sensitive to the loading direction. The deformation mechanism of extruded Mg-Gd-Y magnesium alloy under high stain rate compression is a combination of twinning, slipping and dynamic recrystallization.
Key words: Mg-Gd-Y alloy; split Hopkinson pressure bar; dynamic mechanical property; failure behavior
