@article{Wei2025, 
author = {Shuaihu Wei and Xiaojun Wang and Xuejian Li and Hailong Shi and Xiaoshi Hu and Chao Xu},
title = {Controlled preparation of a novel GNP@MgO particles and its refinement mechanism in Mg-9Al alloy},
year = {2025},
journal = {Journal of Magnesium and Alloys},
volume = {13},
number = {4},
pages = {1536-1548},
keywords = {In-situ reaction, Grain refinement, Mg-9Al alloy, GNP@MgO particle, Al4C3 phase},
url = {https://www.sciopen.com/article/10.1016/j.jma.2024.01.009},
doi = {10.1016/j.jma.2024.01.009},
abstract = {The addition of effective nucleating particles in the melt to achieve grain refinement has become the most widely used method for the casting industries. In this study, a novel GNP@MgO particle with a nanocomposite structure was prepared by utilizing an in-situ reaction of the carbon source gas with Mg melt. The results showed that the particles can significantly reduce the average grain size of Mg-9Al alloy from 130.4 µm to 13.1 µm, and achieve an ultra-high grain refinement efficiency of 90%. The refinement mechanisms are that the Al4C3 phase can act as a heterogeneous nucleation site for α-Mg grains due to the orientation relationship as (001)Al4C3//(002)Mg. Meanwhile, the particle distribution model shows that the velocity of MgO particles is much higher than the growth rate of α-Mg grains. Therefore, it is pushed to the vicinity of grain boundaries during solidification, effectively limiting the growth of α-Mg grains. The remarkable grain refinement effect was achieved through the synergistic modulation of Al4C3 and MgO particles. This work may provide new insight into designing high efficiency grain refiners for Mg-Al alloys.}
}