文献类型：期刊文献

英文题名：Grain-refining and strengthening mechanisms of bulk ultrafine grained CP-Ti processed by L-ECAP and MDF

作者：Zhao, Peng-Cheng[1];Yuan, Guang-Jian[1];Wang, Run-Zi[1];Guan, Bo[2];Jia, Yun-Fei[1];Zhang, Xian-Cheng[1];Tu, Shan-Tung[1]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Minist Educ, Key Lab Pressure Syst & Safety, Shanghai 200237, Peoples R China;[2]Chongqing Univ, Natl Engn Res Ctr Magnesium Alloys, Chongqing 400044, Peoples R China

年份：2021

卷号：83

起止页码：196

外文期刊名：JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY

收录：;EI(收录号：20210709918341);WOS:【SCI-EXPANDED(收录号:WOS:000661886200019)】；

基金：This work was financially supported by the National Natural Science Foundation of China (Nos. 51725503 and 51975211), the Shanghai Super Postdoctoral Incentive Plan, Shanghai Rising Star Program (No. 20QA1402500), and the Innovation Program of Shanghai Municipal Education Commission (No. 2019-01-07-0002-E00068). The authors are also grateful to the Suqian Research Institute of Hohai University and Guangxi University in processing UFG CP-Ti.

语种：英文

外文关键词：Equal channel angular pressing; Multi-directional forging; Ultrafine grain; Recrystallization; Strain hardening; Hall-Petch relation

摘要：The microstructural evolution and mechanical properties of ultrafine-grained (UFG) CP-Ti after an innovative large-volume equal channel angular pressing (L-ECAP) and multi-directional forging (MDF) were systematically examined using monotonic tensile tests combined with transmission electron microscope (TEM) and electron backscatter diffraction (EBSD) techniques. Substantially refined and homogeneous microstructures were achieved after L-ECAP (8-pass and 12-pass) and MDF (2-cycle and 3-cycle), respectively, where the grain size distribution conformed to lognormal distribution. The grain refinement of 450 degrees C L-ECAP is dominated by dynamic recrystallization (DRX) and dynamic recovery (DRV), while that of MDF is dominated by DRX. The iron impurities promote recrystallization by pinning-induced dislocation accumulation so that DRX is prone to occur at iron segregation regions during L-ECAP. The monotonic tensile results show that the strain hardening rate of CP-Ti increases with the decrease of grain size, while the continuous strain hardening ability decreases. The relationship between the average grain size and yield strength is in accordance with Hall-Petch relationship. Meanwhile, the individual strengthening mechanisms were quantitatively examined by the modified model. The results indicate that the strengthening contribution of dislocation accumulation to yield strength is greater than that of grain refinement. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.