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采用定向凝固技术结合液淬法对DZ125合金平界面和枝晶生长条件下溶质的偏析行为进行了研究,通过EPMA定量测定γ基体中各元素的溶质含量和淬火平界面两侧固相和液相中的溶质含量,分别获得了溶质再分配后固相中的溶质分布状态及溶质分配系数.结果表明,平界面生长条件下,液相中的熔体流动使溶质再分布始终处于非稳态.Al,Ti,Ta,Mo和Ni元素的溶质分配系数小于1;而W,Cr和Co元素的溶质分配系数大于1,溶质分布状态满足Scheil模型.枝晶与平界面生长的溶质偏析行为基本一致,然而,固相反扩散显著降低了枝晶生长过程中的溶质偏析.
The segregation behavior of solute in the interface and dendritic growth of DZ125 alloy was investigated by directional solidification combined with liquid quenching. The solute content of each element in γ matrix was measured by EPMA and the solid and liquid phases The solute distribution and the solute partition coefficient in the solid phase after solute redistribution were obtained respectively.The results show that under the condition of flat interface growth, the melt flow in the liquid phase makes the solute redistribution always in an unstable state.Al The solute partition coefficients of Ti, Ta, Mo and Ni are less than 1, while the solute partition coefficients of W, Cr and Co are greater than 1. The solute distribution satisfies the Scheil model. The solute segregation behavior of dendrite and flat interface are basically the same, However, solid phase counter-diffusion significantly reduces solute segregation during dendrite growth.