钢铁材料组织超细化机理的电子理论研究

通过计算机编程建立奥氏体相中的1/2［110］刃位错，用实空间的递推方法计算碳、氮及合金元素在完整晶体及位错区引起的环境敏感镶嵌能，进而讨论碳、氮及合金元素在位错区的 偏聚及交互作用.计算结果表明：分立的轻杂质C，N易偏聚在位错区，它们在刃位错上方形 成柯氏气团；合金元素在完整的奥氏体晶体中趋于均匀分布，强、中碳化物形成元素（Ti, V, Nb, Cr）易在刃位错区偏聚，它们在位错上方形成柯氏气团，而非碳化物形成元素Ni偏 聚于位错线下方，或分布于非缺陷区；轻杂质加剧强碳化物形成元素在刃位错区的偏聚.当 温度下降使得C，N及合金元素的浓度超过其最大固溶度时，在钢的奥氏体刃位错区将有C，N化合物脱溶，这些化合物可作为奥氏体再结晶的异质晶核，细化晶粒. 关键词： 电子结构 位错 超细化

Electronic theory for the refinement mechanism of ultrafine steel

The model of 1/2110] edge dislocation in austenite phase was set up w ith computer programming. The environment-sensitive embedding energy (ESE) of C , N and alloy elements in grains or in the area of edge dislocation was calculate d by using recursion method. The enrichment and interaction of C, N and alloy elements in the area of dislocation were discussed. Calculation resul t s show that: discrete light impurities C and N tend to aggregate in the dislocat ion area, forming Caldwell air mass above the edge dislocation; the alloy elemen t is liable to distribute in perfect austenite grains. Ti, V, Nb and Cr, which are st rong or middling strong elements for carbide formation, are easy to aggregate in the edge dislocation area. They can also form the Caldwell air ma ss above the edge dislocation like C or N. But Ni, which is non_carbide formatio n element, aggregates below the dislocation line or distributed in the perfect g rains. The light impurity can enforce the aggregation of strong carbide forming elements in the edge dislocation area. When the temperature is decreased, and wh en the concentration of C, N and alloy elements reach the high limit of concen tration, the C, N compound of alloying elements will precipitate from the matrix in t he edge dislocation area of austenite in the steel. These compounds can act as h eter ogeneous nuclei of austenite phase in the course of recrystallization, lea ding to the refinement of austenite grains.