|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Magnesium Technology 2016
||P-11: Grain Refinement Mechanism of Magnesium by Addition of Calcium
||Guosheng Peng, Yun Wang, Zhongyun Fan
|On-Site Speaker (Planned)
Grain refinement mechanism of Mg by Ca addition was investigated. It was shown that, with only 100 ppm Ca addition, fully columnar to equiaxed transition (CET) and significant decrease in grain size were observed. With Ca concentration increasing from 100 ppm to 1 wt. %, the equiaxed grain size further decreased. With melt shearing imposed, the grain structure was all equiaxed and the grain size almost kept constant when Ca concentration varied from 0 to 0.5 wt.%. The grain size continued to decrease to as fine as 70 Ám with Ca concentration increasing to 1 wt.%. High resolution TEM revealed that there were specific orientation relationships between in-situ MgO particles and Mg grains, indicating that the MgO particles were the potent nucleation inoculants. Discussion was focused on the modification of MgO surface by the adsorption and/or segregation of Ca atoms and the resultant effect on the heterogeneous nucleation mechanism.
||Planned: A combination print-CD volume