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通过背散射电子衍射(EBSD)研究Al-8Zn和Al-6Bi-8Zn两种合金经5道次室温等径角挤压(ECAP)过程中的组织演变和晶粒细化行为。经过5道次等径角挤压,两种合金都形成了超细晶粒。然而,Al-6Bi-8Zn合金的晶粒明显小于Al-8Zn合金,这说明在等径角挤压过程中铋粒子对晶粒细化有明显的作用。通过测定等径角挤压后两种合金的硬度发现,经5道次等径角挤压之后,Al-6Bi-8Zn合金的硬度高于Al-8Zn合金。此外,讨论了铋粒子在等径角挤压过程中对变形行为及最终合金强度的影响。
The microstructure evolution and grain refinement behavior of Al-8Zn and Al-6Bi-8Zn alloys during 5 passes of ECAP at room temperature were studied by backscattered electron diffraction (EBSD). After 5 passes of equal diameter angular extrusion, both alloys formed ultra-fine grains. However, the grain size of Al-6Bi-8Zn alloy is significantly smaller than that of Al-8Zn alloy, indicating that the bismuth particles have a significant effect on the grain refinement during the isopipe extrusion. By measuring the hardness of the two alloys after ECAP, it was found that the hardness of Al-6Bi-8Zn alloy was higher than that of Al-8Zn alloy after five times of ECAP. In addition, the influence of bismuth particles on the deformation behavior and the final alloy strength during isobaric angle extrusion was discussed.