物理学报2017，Vol.66Issue(16)：316-323,8.DOI:10.7498/aps.66.168101
合金元素对钢中NbC异质形核影响的第一性原理研究
First-principles calculation of influence of alloying elements on NbC heterogeneous nucleation in steel
摘要
Abstract
The NbC precipitated in steel is in favor of the heterogeneous nucleation of ferrite, which is affected by the alloying elements at the ferrite/NbC interface. However, it is difficult to clearly understand the effect of alloying elements on the ferrite/NbC interface behavior experimentally. Therefore, the first-principles calculation is employed to address this problem in this paper. First of all, the segregation behaviors of alloying element X(=Cr, Mn, Mo, W, Zr, V, Ti, Cu and Ni) on the ferrite(100)/NbC(100) interface are systematically explored. And then, we investigate the influences of these alloying elements on the property of the ferrite/NbC interface. The work of adhesion (Wad), interfacial energy (γint) and electronic structure of ferrite/NbC interface alloyed by these elements are also analyzed. The results show that the (Cr, V, Ti)-doped interfaces have negative segregation energies, which indicates that Cr, V and Ti are easily segregated at the ferrite/NbC interface. Conversely, the Mn, W, Mo, Zr, Cu and Ni are difficult to segregate at the interface. When Mn, Zr, Cu and Ni replace the Fe atoms in the ferrite/NbC interface, the adhesive strength of the interface will decrease, thus weakening the heterogeneous nucleation of ferrite on NbC surface. However, the introduction of Cr, W, Mo, V and Ti will improve the stability of the ferrite/NbC interface due to the larger Wad and lower γint. Therefore, the Cr, W, Mo, V and Ti on the ferrite side of the interface can effectively promote ferrite heterogeneous nucleation on NbC surface to form fine ferrite grain. The analysis of difference charge density indicates that after the introduction of Zr and Cu in ferrite/NbC interface, the interactions among interfacial Zr, Cu and C atoms was weaken. However, when Cr and W are introduced into the clean interface, the strong Cr-C and W-C non-polar covalent bonds are formed, which enhances the adhesion strength of the ferrite/NbC interface. In addition, the minimum Cr-C bonding length at the Cr-doped interface suggests that the interface has the highest interface strength. The Mulliken population analysis shows that for the (Cr, W, Mo, V, Ti)-doped interfaces, the transfer charges of Cr, W, Mo, V and Ti are 1.12, 0.84, 0.54, 0.33 and 0.28, respectively. Nevertheless, for the clean interface, the transfer charge of Fe is only 0.05. Therefore, the interactions among interfacial Cr, W, Mo, V, Ti and C atoms are stronger than that between interfacial Fe and C atoms, which is in good accordance with the above analysis.关键词
合金元素/异质形核/NbC/第一性原理Key words
alloying elements/heterogeneous nucleation/NbC/first-principles引用本文复制引用
熊辉辉,刘昭,张恒华,周阳,俞园..合金元素对钢中NbC异质形核影响的第一性原理研究[J].物理学报,2017,66(16):316-323,8.基金项目
国家自然科学基金(批准号:51404113,51404110)和江西理工大学创新训练项目(批准号:XZG-16-08-14)资助的课题.Project supported by the National Natural Science Foundation of China (Grant Nos.51404113,51404110) and Innovation Training Program of Jiangxi University of Science and Technology,China (Grant No.XZG-16-08-14). （批准号:51404113,51404110）
