中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 34 No. 8 August 2024 |
（1. School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Brunel Centre for Advanced Solidification Technology (BCAST), Brunel University London, Uxbridge, Middlesex UB8 3PH, United Kingdom）
Abstract:The effect of addition temperature of MgO particles (MgOp) on their dispersion behavior and the efficiency of grain refinement in AZ31 Mg alloy was investigated. In addition, the grain refinement mechanism was systematically studied by microstructure characterization, thermodynamic calculation, and analysis of solidification curves. The results show that the grain size of AZ31 Mg alloy initially decreases and then increases as the MgOp addition temperature is increased from 720 to 810 °C, exhibiting a minimum value of 136 μm at 780 °C. The improved grain refinement efficiency with increasing MgOp addition temperature can be attributed to the reduced Mg melt viscosity and enhanced wettability between MgOp and Mg melt. Furthermore, a corresponding physical model describing the solidification behavior and grain refinement mechanism was proposed.
Key words: grain refinement; MgO nucleation particles; AZ31 alloy; addition temperature; dispersion behavior
