Microstructure Evolution in Undercooled Ni-Si Melt
Upon non-equilibrium solidification,the intrinsic parameters,such as moving velocity,temperature,solute partition coefficient,and liquid and solid concentrations at the interface,deviate from their equilibrium characteristics,and the morphology of the as-solidified structure and the grain size are influenced by the non-equilibrium liqulid/solid transformation,which further influences the subquent solid–state transformation.Adopting molten glass purification technology combined with cycle superheating method,the microstructure evolution of Ni-11at.%Si alloy in different undercooling was investigated.It was found that,with the increase of the initial undercooling,grain refinement occurred in microstructures of undercooled Ni-11at.%Si alloy.Meanwhile,the NL model was used to discuss the two different dendrite morphologies.According to Karmas model for dendrite fragmentation,the grain refinement of undercooled Ni-11at.%Si alloy was in good agreement with the experimental data,and the grain size was reduced with the increasing ΔT.The energy-dispersive spectroscopy (EDS) measurement was applied to analyze the solid solubility of Si atom in α-Ni matrix.It was found that the solid solubility of Si atom in α-Ni matrix increased with undercooling.At the undercooling of ΔT>220K,a complete solute trapping occurred.
Undercooling Crystal growth Ni-Si alloy
Kai Fan Feng Liu Wenzhong Luo Yaohe Zhou
Western Superconducting Technologies Co., Ltd., Xian 710018, China Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian, Shanxi 71
国际会议
the Chinese Materials Congress 2012(2012年中国材料大会(CMC2012))
太原
英文
349-355
2012-07-13（万方平台首次上网日期，不代表论文的发表时间）