累积挤压工艺制备纯铝的晶粒细化及力学性能

来源期刊：中国有色金属学报(英文版)2019年第3期

论文作者：陈祥 黄光胜 刘帅帅 韩廷状 蒋斌 汤爱涛 朱运田 潘复生

文章页码：437 - 447

关键词：铝；累积挤压结合；显微组织；力学性能；应变硬化率

Key words：aluminum; accumulative extrusion bonding; microstructure; mechanical properties; strain hardening rate

摘    要：研究一种新的剧烈塑性变形技术，即累积挤压结合(AEB) 加工超细晶粒铝。显微组织表征结果表明，界面结合良好，6道次后样品的平均晶粒尺寸约为440 nm。拉伸试验结果表明，5道次后样品的抗拉强度达到最大值195 MPa，总伸长率超过16%；样品的硬度也显著提高，且在第1道次后几乎达到饱和。累积挤压加工的样品经拉伸试验后的扫描电镜断口形貌表明，断裂模式为剪切韧性断裂，同时出现细长浅韧窝。与传统累积叠轧工艺相比，此新型累积挤压技术在细化晶粒和改善力学性能方面更有效。

Abstract: Ultrafine-grained aluminum processed by a new severe plastic deformation technique, accumulative extrusion bonding (AEB), was investigated. Microstructural characterization indicated good interfacial bonding and an average grain size of ~440 nm was obtained after six passes. Tensile testing revealed that the strength reached the maximum value of 195 MPa and the total elongation exceeded 16% after five passes. The hardness was also significantly improved and almost reached saturation after the first pass. SEM fractography of AEB-processed specimens after tensile test showed that failure mode was shear ductile fracture with elongated shallow dimples. Comparison with conventional accumulative roll bonding indicates that this new AEB technique is more effective in refining grain and improving mechanical properties of the specimens.