Ab initio investigations of the phase stability in group IVB and VB transition metal carbides
Ab initio investigations of the phase stability in group IVB and VB transition metal carbides
复制标题
DOI：
10.1016/j.commatsci.2015.10.038
复制
发表时间：
2016-02
影响因子：
3.3
通讯作者：
Xiao-xiang Yu;C. Weinberger;G. Thompson
中科院分区：
文献类型：
--
作者：
Xiao-xiang Yu;C. Weinberger;G. Thompson
采用从头算方法研究了IVB族和VB族过渡金属碳化物在常压和0 K下的稳定性。通过比较这些相的形成焓、空位扩散激活能和广义堆垛层错能，发现碳化物之间存在空位有序相和堆垛层错相形成机制之间的热力学竞争。通常，IVB族碳化物具有比VB族碳化物更高的空位迁移能，这可以解释在实验中形成这种空位有序相的困难。此外，IVB族碳化物不具有存在于VB族碳化物中的稳定的本征堆垛层错（ISF）。该ISF用于合理化IVB族碳化物中不存在这种故障相，但它们存在于VB族碳化物中。
Usingab-initio calculations, the stability of various stable and metastable group IVB and VB transition metal carbide compounds at ambient pressure and 0 K were investigated. By comparing the formation enthalpy, vacancy diffusion activation energy and generalized stacking fault energy of these phases, the thermodynamic competition between vacancy-ordered and stacking-faulted phase formation mechanisms are seen among the carbides. In general, the group IVB carbides have a higher vacancy migration energy than that of the group VB carbides which could explain the difficulty in experimentally forming such vacancy-ordered phases. In addition, the group IVB carbides do not have a stable intrinsic stacking fault (ISF), which is present in the group VB carbides. This ISF is used to rationalize the absence of such faulted phases in the group IVB carbides but their presence in the group VB carbides.