【摘要】 通过计算机编程建立了钢铁中铁素体相中的1/2[1 1 1]刃位错的原子结构模型,用实空间的连分数方法计算了碳、氮及合金元素在完整晶体及位错区引起的总结构能和环境敏感镶嵌能,讨论了碳、氮及合金元素在位错区的偏聚及交互作用.计算结果表明:轻杂质C,N易偏聚于位错芯处;强、中碳化物形成元素(Ti,V,Nb,Cr)易偏聚于刃位错线上,非碳化物形成元素Ni偏聚于位错线下方的弹性扩张区;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,钢铁中刃位错区将有C,N金属间化合物脱溶,这些化合物会阻碍位错的运动,起到第二相粒子的强化作用.更多还原

【Abstract】 The atomic structure model of 1/2 edge dislocation in ferrite phase of steel or iron was set up with computation programmed.The environment-sensitive embedding energy(ESE) and total structure energy of C,N and other alloy elements in grains or in dislocation area were calculated by recursive method separately.The aggregation of and interaction among C,N and alloy elements in dislocation area were discussed.Calculation results showed that the light impurities C and N tend to aggregate at the core of edge dislocation and all the edge dislocations are tied together and can not move freely.The elements Ti,V,Nb and Cr,are formed by strong or moderate carbides and easy to aggregate on the edge dislocation line,but Ni,as not formed by carbides,aggregates in the elastic expansion area below the dislocation line.The light impurities aggravate the aggregation of the elements formed by strong carbides on the edge dislocation lines.Thus,when lowering the temperature the concentrations of C and N and alloy elements exceed the solid solubility limit,and the C and N intermetallic compounds precipitate in the edge dislocation area of ferrite in steel or iron.These compounds will retard the movement of dislocations to cause the strengthening of steel or iron.更多还原