Microstructural Evolution at Micro/Meso-Scale in an Ultrafine-Grained Pure Aluminum Processed by Equal-Channel Angular Pressing with Subsequent Annealing Treatment

Jie Xu; Jianwei Li; Xiaocheng Zhu; Guohua Fan; Debin Shan; Bin Guo

doi:10.3390/ma8115391

Microstructural Evolution at Micro/Meso-Scale in an Ultrafine-Grained Pure Aluminum Processed by Equal-Channel Angular Pressing with Subsequent Annealing Treatment

Materials (Basel). 2015 Nov 4;8(11):7447-7460. doi: 10.3390/ma8115391.

Authors

Jie Xu^{1

2}, Jianwei Li³, Xiaocheng Zhu⁴, Guohua Fan⁵, Debin Shan^{6

7}, Bin Guo^{8

9}

Affiliations

¹ Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin 150080, China. xjhit@hit.edu.cn.
² School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China. xjhit@hit.edu.cn.
³ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China. 13B909069@hit.edu.cn.
⁴ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China. zhuxc.hit@gmail.com.
⁵ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China. ghfan@hit.edu.cn.
⁶ Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin 150080, China. shandebin@hit.edu.cn.
⁷ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China. shandebin@hit.edu.cn.
⁸ Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin 150080, China. guobin@hit.edu.cn.
⁹ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China. guobin@hit.edu.cn.

Abstract

Micro-forming with ultrafine-grained (UFG) materials is a promising direction for the fabrication of micro-electro-mechanical systems (MEMS) components due to the improved formability, good surface quality, and excellent mechanical properties it provides. In this paper, micro-compression tests were performed using UFG pure aluminum processed by equal-channel angular pressing (ECAP) with subsequent annealing treatment. Microstructural evolution was investigated by electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM). The results show that microstructural evolutions during compression tests at the micro/meso-scale in UFG pure Al are absolutely different from the coarse-grained (CG) materials. A lot of low-angle grain boundaries (LAGBs) and recrystallized fine grains are formed inside of the original large grains in CG pure aluminum after micro-compression. By contrast, ultrafine grains are kept with few sub-grain boundaries inside the grains in UFG pure aluminum, which are similar to the original microstructure before micro-compression. The surface roughness and coordinated deformation ability can be signmicrostructure; micro/meso-forming; ultrafine grains; ECAP; aluminumificantly improved with UFG pure aluminum, which demonstrates that the UFG materials have a strong potential application in micro/meso-forming.

Keywords: ECAP; aluminum; micro/meso-forming; microstructure; ultrafine grains.