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

作     者：Peng-Cheng Zhao Guang-Jian Yuan Run-Zi Wang Bo Guan Yun-Fei Jia Xian-Cheng Zhang Shan-Tung Tu Peng-Cheng Zhao;Guang-Jian Yuan;Run-Zi Wang;Bo Guan;Yun-Fei Jia;Xian-Cheng Zhang;Shan-Tung Tu

作者机构：Key Laboratory of Pressure Systems and SafetyMinistry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai200237China National Engineering Research Center for Magnesium AlloysChongqing UniversityChongqing400044China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2021年第83卷第24期

页      面：196-207页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：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) the Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-0002-E00068) 

主　　题：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)*** 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 *** grain refinement of450℃L-ECAP is dominated by dynamic recrystallization(DRX)and dynamic recovery(DRV),while that of MDF is dominated by *** iron impurities promote recrystallization by pinning-induced dislocation accumulation so that DRX is prone to occur at iron segregation regions during *** 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 *** relationship between the average grain size and yield strength is in accordance with Hall-Petch ***,the individual strengthening mechanisms were quantitatively examined by the modified *** results indicate that the strengthening contribution of dislocation accumulation to yield strength is greater than that of grain refinement.