亚稳FCC Ti的点阵常数评估

Assessments of Lattice Parameters of Metastable FCC Ti

在高能机械研磨过程以及薄膜和多层复合材料中观察到了亚稳态FCC Ti。但已有文献报道的FCC Ti的点阵常数具有很大差异。采用两种方法研究了亚稳块状(粗晶)FCC Ti的点阵常数:(1)由稳定的含Ti二元FCC合金的试验数据直接外推;(2)二元FCC合金的第一性原理计算。由于大多试验数据来源于纳米尺度的Ti晶体,故在上述两种方法的基础上进一步研究了晶粒尺寸效应对纳米晶FCC Ti点阵常数的影响,最终评估得到的亚稳态FCC Ti的点阵常数与测量值吻合较好。

Metastable FCC Ti has been observed in high-energy mechanical milling process,as well as in thin films and multilayer composites.The reported lattice parameters of FCC Ti were very different.Two methods,i.e.,(1)extrapolation from the experimental data of stable Ti-containing binary FCC alloys,(2)first-principle calculations for binary FCC alloys,were adopted to study the lattice parameters of metastable bulk FCC Ti(coarse grains).Because the experimental measurements were mostly performed for nanocrystalline Ti,therefore,on the basis of the above two methods,a further study of the effect of grain size on the lattice parameters of nanocrystalline FCC Ti was conducted.Finally,the assessed lattice parameters of metastable FCC Ti were in good agreement with the measured values.