摘要
通过计算机编程建立钢奥氏体相中Σ5〈001〉/(210)大角晶界模型,用实空间的递推方法计算碳、氮及微合金元素在完整晶体及晶界区引起的环境敏感镶嵌能,进而讨论碳、氮及微合金元素在晶界区的偏聚及交互作用.计算结果表明,轻杂质C,N易偏聚于晶界区,且形成气团;微合金元素在完整的奥氏体中趋于均匀分布,Ti,V,Nb易占位于晶界三角棱柱的顶部(压缩区),且其加入量足够大时,它们能够在晶界区形成气团;微合金元素能够偏聚于C,N掺杂的大角晶界区,当温度下降使得C,N及微合金元素的浓度超过其最大固溶度时,在钢的奥氏体晶界区将有C,N化合物脱溶,这些化合物既可成为奥氏体再结晶的异质晶核,又可以阻碍奥氏体晶粒长大,故可起到细化晶粒作用.在微合金元素中Nb的细化效果最好.
A model of ∑5 （001）/（210） high angle grain boundary （GB） in austenite phase in steel was set up with computer programming. The environment-sensitive embedding energies （ESE） of C, N and microalloying elements in grains or in GB core are calculated by recursion method, respectively. The segregation and interaction of C, N and microalloying elements in the GB core were discussed. Calculation results show that： discrete light impurities C and N tend to segregate in the GB area, forming atomic clusters; microalloying elements are liable to distribute.in perfect austenite grains. Ti, V, Nb occupy the top sites of the trigonal prism formed by iron in the GB core, and Ti, V, Nb can also form atomic clusters in GB core like C or N. When the temperature is decreased and the concentration of C, N and microalloying elements reach to the limit of solubility, the C, N compounds of microalloying elements precipitate from the matrix in GB core of austenite in steel. These compounds can act as heterogeneous nuclei of austenite phase in the course of recrystallization and retard the growth of austenite grains, leading to the refinement of austenite grains. Nb is the most efficient refiner of microalloying elements Nb, Ti, V.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2006年第3期1369-1373,共5页
Acta Physica Sinica
基金
辽宁省教育厅科学研究计划(批准号:2004C008)
中国博士后科学基金(批准号:2004036113)
国家高科技研究发展计划(批准号:2003AA331120)
沈阳师范大学实验中心资助的课题.~~
关键词
电子结构
晶界偏聚
超细化
electronic structure, grain boundary, super-refinement
