中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 26 No. 4 April 2016 |
（1. Institute of Materials Physics and Chemistry, School of Materials Science and Engineering,
Northeastern University, Shenyang 110819, China;
2. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China;
3. Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education,
Northeastern University, Shenyang 110819, China）
Abstract:To explore the effect of strain rate on the high temperature deformation characteristics of ultrafine-grained materials, the deformation and damage features as well as microstructures of ECAP-treated pure Al at different temperatures T and strain rates were systematically studied through compression tests and microscopic observations. The increase in eliminates strain softening at T≤473 K, and largely enhances the yield strength and flow stress at 473-573 K. The shear deformation dominates the plastic deformation of ECAP-treated Al. Many cracks along shear bands (SBs) are formed at T≥473 K and secondary SBs basically disappear at 1×10-3 s-1; however, at 1×10-2 s-1, cracks are only observed at temperature below 473 K, and secondary SBs become clearer at T≥473 K. The microstructures of ECAP-treated Al mainly consist of sub-grains (SGs). The increase in inhibits the SG growth, thus leading to the increases both in yield strength and flow stress at high temperatures.
Key words: equal channel angular pressing (ECAP); pure Al; strain rate; high temperature compression; deformation; damage; microstructure
