Segregation of impurity to the grain boundary and interphase boundary in ultra-fine microstructure

本文从理论和实验两方面研究了晶粒尺寸对晶界偏聚的影响，结果表明：（1）溶质向晶界的平衡偏聚可用修正的姆克林方程描述：2.晶粒尺寸对晶间偏析的影响显著，随着温度的降低，偏析能增大，体相浓度降低。3.在A-X-Y三元合金中，当X元素的偏析自由能大于Y元素时，X原子的晶界浓度随晶粒尺寸的减小而减小，而Y原子的晶界浓度则取决于溶质的体浓度5.计算了Bi在Cu中的偏聚能为62.5kJ/mol。6.表明晶粒尺寸对金属系和陶瓷系的晶界偏聚有重要影响。

Theoretical and experimental study of the effect of grain size on the grain boundary segregation was made and the results obtained are as follows ;1.The equilibrium segregation of solute to the grain boundary can be described by the modified Mclean's equation :2.The grain size effect on the intergranular segregation is remarkable with higher segregation energies and lower bulk concentrations with decreasing temperature.3.When the segregation free energy of X is larger than that of Y in A-X-Y ternary alloy, the grain boundary concentration of X atom decreases with decreasing grain size, while that of Y atom depends on the bulk concentrations of solute.4.An experimental evidence of the grain size dependence of the intergranular segregation in Cu-0.0015at.%Bi alloy was obtained.5.The segregation energy of Bi in Cu was estimated to be about 62.5kJ/mol.6.It is suggested that the grain size has a significant role on the grain boundary segregation not only in the metallic system but also in ceramics.