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 stru...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 130.4μm to 13.1μm,and achieve an ultra-high grain refinement efficiency of 90%.The refinement mechanisms are that the Al_(4)C_(3)phase can act as a heterogeneous nucleation site forα-Mg grains due to the orientation relationship as(001)_(Al_(4)C_(3))//(002)Mg.Meanwhile,the particle distribution model shows that the velocity of MgO particles is much higher than the growth rate ofα-Mg grains.Therefore,it is pushed to the vicinity of grain boundaries during solidification,effectively limiting the growth ofα-Mg grains.The remarkable grain refinement effect was achieved through the synergistic modulation of Al_(4)C_(3)and MgO particles.This work may provide new insight into designing high efficiency grain refiners for Mg-Al alloys.展开更多
基金supported by the National Natural Science Foundation of China(grant nos.52301142,52371107,52201115)Heilongjiang Provincial Postdoctoral Science Foundation(grant no.LBH-11Z22167).
文摘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 130.4μm to 13.1μm,and achieve an ultra-high grain refinement efficiency of 90%.The refinement mechanisms are that the Al_(4)C_(3)phase can act as a heterogeneous nucleation site forα-Mg grains due to the orientation relationship as(001)_(Al_(4)C_(3))//(002)Mg.Meanwhile,the particle distribution model shows that the velocity of MgO particles is much higher than the growth rate ofα-Mg grains.Therefore,it is pushed to the vicinity of grain boundaries during solidification,effectively limiting the growth ofα-Mg grains.The remarkable grain refinement effect was achieved through the synergistic modulation of Al_(4)C_(3)and MgO particles.This work may provide new insight into designing high efficiency grain refiners for Mg-Al alloys.
基金National Natural Science Foundation of China(51301118,51404166)International Cooperation in Shanxi(2014081002)Technological Innovation Programs of Higher Education Institutions in Shanxi(2013108)
