研究晶粒尺寸和析出相的双重异质结构对小挤压比制备的AZ91挤压板材力学性能的影响.与挤压比(ER)为12.8的样品(即ER12.8样品)相比,ER3.9和ER6.4样品呈现明显的粗细晶粒层和异质分布的细小弥散的析出相.此外,在ER3.9样品的细晶层中还观察到大量带状析出相.由于异质变形诱导(HDI)力和析出相的平衡,ER6.4样品呈现良好的强度和塑性结合.尽管ER3.9样品表现出最高的HDI力和基面滑移施密特因子,改善了塑性,但更多的带状析出相对恶化其力学性能仍起主导作用.
The influence of dual-heterostructure of grain size and precipitates on the mechanical properties of the AZ91 alloy extruded sheet prepared by small extrusion ratio was investigated. Compared to the sample with the extrusion ratio (ER) of 12.8 (i.e., ER12.8 sample), the ER3.9 and ER6.4 samples present a remarkable coarse and fine-grained layers with heterogeneous fine-dispersed precipitates. Moreover, a large number of banded precipitates are observed in the fine-grained layers of the ER3.9 sample. The ER6.4 sample has an excellent combination of strength and ductility due to a balance of heterogeneous deformation-induced (HDI) stress and precipitates. Although the ER3.9 sample shows the highest HDI stress and Schmid factor for basal slip to improve ductility, more banded precipitates still play a dominate role in deteriorating its mechanical properties.