ABSTRACT In this study, the as-cast commercially pure aluminum 1A85 was prepared through continuous variable cross-section recycled extrusion (CVCE) technique at room temperature(300 K) to investigate the effect of number of CVCE passes on its microstructure and mechanical properties. The results showed that the ultrafine-grained pure Al with the average grain size of 0.4 μm could be obtained after 3 passes, which was 1/210 of the original grain size. Besides, the grain size of specimen was gradually decreased when the number of CVCE passes was increased from 1 to 3 passes, while the dislocation density was elevated. As a result, the highest average microhardness, yield strength and ultimate tensile strength could be obtained after 3 passes. However, the mechanical properties of the as-prepared specimen were substantially reduced after 4 passes. Moreover, differences in mechanical properties between the cross and longitudinal sections could be attributed to the grain size and dislocation substructures. Taken together, the grain refinement and dislocation strengthening had significant effect on the mechanical properties of the CVCE-prepared pure Al.

中文翻译：

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CVCE 道次对铸态商业纯铝 1A85 组织和性能的影响

摘要 在本研究中，通过连续可变截面回收挤压 (CVCE) 技术在室温 (300 K) 下制备了铸态商业纯铝 1A85，以研究 CVCE 道次数量对其微观结构和机械性能的影响。结果表明，经过3道次后可得到平均晶粒尺寸为0.4 μm的超细晶纯Al，为原始晶粒尺寸的1/210。此外，当CVCE道次从1道次增加到3道次时，试样晶粒尺寸逐渐减小，而位错密度升高。结果，3道次后可获得最高的平均显微硬度、屈服强度和极限抗拉强度。然而，所制备试样的机械性能在 4 次通过后显着降低。此外，横截面和纵向截面之间机械性能的差异可归因于晶粒尺寸和位错亚结构。总之，晶粒细化和位错强化对 CVCE 制备的纯铝的力学性能有显着影响。