中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 30 No. 9 September 2020 |
（1. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia）
Abstract:TiC nanoparticle-reinforced Mg-4Zn-0.5Ca matrix nanocomposites were processed by combining multidirectional forging (MDF) and extrusion (EX). The grain size of the nanocomposite after MDF+EX multi-step deformation was significantly decreased compared with that processed only by MDF. The average size of the recrystallized grains gradually increased after EX with increasing the number of MDF passes at 270 °C. However, the grain size significantly decreased by MDF processing at 310 °C. Both fine and coarse MgZn2 phases appeared in the (MDF+EX)-processed nanocomposites, and their volume fractions gradually increased with increasing the number of MDF passes before EX. Ultrahigh tensile properties (yield strength of ~404 MPa, ultimate tensile strength of ~450.3 MPa and elongation of ~5.2 %) were obtained in the nanocomposite after three MDF passes at 310 °C followed by EX. This was attributed to the refinement of the recrystallized grains, together with the improved Orowan strengthening provided by the precipitated MgZn2 particles that were generated by MDF+EX multi-step deformation.
Key words: magnesium matrix nanocomposite; multi-step deformation; multidirectional forging; mechanical properties; MgZn2 phases
