溶质原子晶界偏聚动力学过程的数值模拟  

Dynamic process simulation of solute grain boundary segregation

作　　者：吴平[1] 贺信莱[2] 

机构地区：[1]北京科技大学应用科学学院,北京100083 [2]北京科技大学材料科学与工程学院,北京100083

出　　处：《北京科技大学学报》2005年第3期312-316,共5页Journal of University of Science and Technology Beijing

基　　金：国家重点基础研究发展规划(973)资助项目(No.G19980601507)

摘　　要：建立了溶质原子在晶界的平衡偏聚、非平衡偏聚、晶界偏聚溶质向沉淀析出转化以及冷却速度等因素的晶界偏聚物理模型和数学模型.模型考虑了晶界及晶界附近扩展畸变区对溶质的吸附作用和吸附能力.对含硼0.0010%的Fe-40%Ni-B合金体系从1150℃连续冷却到640℃的过程中硼的晶界偏聚状态进行了模拟计算.计算表明,晶界区域硼富集因子在降温初期增加较快,随后增幅变缓,模拟数据显示过程中有晶界区域硼原子向晶内的反向扩散;当晶界上偏聚的硼转化为析出物时,晶界区域富集因子的增加再次变快.模拟计算结果与已发表的实验结果吻合较好.A physical and a mathematic model of solute grain boundary segregation were developed which synthetically took account of both equilibrium and non-equilibrium grain boundary segregation, transformation of segregated solute to precipitates and cooling rate. The adsorption and adsorptivity of grain boundaries and extended disordered zones in the vicinity of grain boundaries to solute atoms were considered. The evolution of boron grain boundary segregation during cooling from 1150°C to 640°C in the Fe-40%Ni-B alloy with 0.0010% boron was simulated. The simulated results show that the boron enrichment factor of the boundary zones increases fast at the beginning of cooling, then relatively even, indicating the back diffusion of segregated boron atoms. After boron precipitates appearing, the enrichment factor increases fast again. Good agreement between experimental and simulated results was achieved.

关 键 词：晶界 扩散 偏聚 硼 

分 类 号：TG111.2[金属学及工艺—物理冶金]