Al-6Mg-0.8Zn-0.5Mn-0.2Zr-0.2Er合金高强耐损伤工艺与微观组织研究

The investigation on the process and microstructure with high strength and high damage tolerance in Al-6Mg-0.8Zn-0.5Mn-0.2Zr-

摘要:

以Al-6Mg-0.8Zn-0.5Mn-0.2Zr-0.2Er合金为基础，对该材料的冷轧态，温轧态，完全退火态进行拉伸测试和疲劳裂纹扩展速率测试。运用电子背散射衍射（EBSD），透射电镜（TEM），扫描电镜（SEM）对合金的原始组织，疲劳断口,裂纹扩展路径进行观察，研究微观组织对材料拉伸性能及疲劳裂纹扩展速率的影响。结果表明：温轧态屈服强度高，裂纹扩展抗力大，实现了高强高耐损伤性能的匹配。这主要是由于温轧态轧制过程中发生动态回复，位错缠结规整化，具有较多的亚晶界，该种组织模式对材料的屈服强度和疲劳裂纹扩展抗力均有提高。

Abstract:

The tensile strength and fatigue crack propagation rate test were carried out for cold rolled, warm rolled and full annealed Al-6Mg-0.8Zn-0.5Mn-0.2Zr-0.2Er alloy. The microstructure before fatigue test , the fatigue fracture and crack propagation path were observed by using electron back-scattered diffraction(EBSD), transmission electron microscope(TEM) and scanning electron microscope(SEM) in order to analyze the effects of microstructure on tensile property and fatigue crack propagation property. The results show that the fatigue crack propagation rate of warm rolled alloy with high strength is much slower than the cold rolled. The microstructure characterization shows that the warm rolled alloy has more subgrain boundaries than that of the cold rolled and full annealed alloys due to dynamic recovery during warm rolling. This kind of microstructure is conducive to the improvement of yield strength and fatigue crack propagation resistance.