Al-Zn-Mg-Cu-Sc合金的退火再结晶机制研究

Mechanism on Annealing Recrystallization of Al-Zn-Mg-Cu-Sc Alloy

摘要:

制备了一种含Sc的Al-Zn-Mg-Cu合金, 采用光学显微镜、扫描电镜、透射电镜技术，运用晶界和晶粒拓扑理论研究、分析了该合金的再结晶组织和规律。结果表明：合金中添加0.15%Sc，可以明显提高再结晶温度。在总变形量一定的条件下，随应变速率增加，合金再结晶过程加快。变形局部化所形成的强剪切变形区，可以看作是没有溶质和溶剂原子的“真空”区域。固溶处理时，该区以界面弓出机制进行再结晶形核，以亚晶吞并机制长大。进入“真空”区域内的溶质和溶剂原子，通过组装过程完成“二次晶体”的重建。淬火的“二次晶体”中保留有大量的空位，溶质原子在空位处偏聚，并通过吸收周围的溶质原子长大

Abstract:

Microstructure and recrystallization behaviour were studied for a sort of Al-Zn-Mg-Cu-Sc alloy in different conditions by means of OM and SEM with EDS and TEM, as well as using topology for grain and boundary. The results show that the recrystallization temperature can be obviously increased with addition of 0.15%Sc to base alloy. The course of recrystallization is speeded up with increasing the velocity of strain at a constant total distortion. Under the condition of dissymmetrical deformation, there are some shear bands or cracks in the region, which can be looked as an “empty zone” without any solute or solvent. It is found that the deformation boundary bending leads to recrystallization nucleation, and the subgrain rotation coalescence leads to growth. The “secondary crystal”is accomplished by the assembly of solute or solvent atoms entering the “empty zone” by diffusing, with a lot of vacancies and solute atoms segregating in the vacancies