中國(guó)有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 12 December 2014 |
（1. National Engineering Research Center of Light Alloy Net Forming,
Shanghai Jiao Tong University, Shanghai 200030, China;
2. Department of Materials Science and Engineering, Norwegian University of Science and Technology,
Trondheim 7491, Norway;
3. ERC for Revolutionizing Metallic Biomaterials, North Carolina A&T State University,
Greensboro, NC 27411, USA;
4. School of Applied Science, Taiyuan University of Science and Technology, Taiyuan 030024, China;
5. School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
6. Center for Advanced Materials, Qatar University, Doha POB 2713, Qatar）
Abstract:Grain refinement of AZ31 Mg alloy during cyclic extrusion compression (CEC) at 225-400 °C was investigated quantitatively by electron backscattering diffraction (EBSD). Results show that an ultrafine grained microstructure of AZ31 alloy is obtained only after 3 passes of CEC at 225 °C. The mean misorientation and the fraction of high angle grain boundaries (HAGBs) increase gradually by lowering extrusion temperature. Only a small fraction of twinning is observed by EBSD in AZ31 Mg alloys after 3 passes of CEC. Schmid factors calculation shows that the most active slip system is pyramidal slip and basal slip {0001} at 225-350 °C and 400 °C, respectively. Direct evidences at subgrain boundaries support the occurrence of continuous dynamic recrystallization (CDRX) mechanism in grain refinement of AZ31 Mg alloy processed by CEC.
Key words: magnesium alloys; grain refinement; continuous dynamic recrystallization (CDRX); electron backscattering diffraction (EBSD); cyclic extrusion compression (CEC)
