论文标题
通过第一原理理论和原子建模：NBMOTA，NBMOTAW和VNBMOTAW，难治性高渗透合金中的短期顺序和组成相稳定性
Short-range order and compositional phase stability in refractory high-entropy alloys via first principles theory and atomistic modelling: NbMoTa, NbMoTaW and VNbMoTaW
论文作者
论文摘要
使用全电子，第一原理，Landau型理论，我们研究了等值式难治性高熵合金，NBMOTA，NBMOTAW和VNBMOTAW中短距离顺序和组成相稳定性的性质。我们还研究了选定的二进制子系统，以洞悉驱动顺序的物理机制。我们的方法直接检查了固体溶液的短距离顺序，渗透障碍/顺序转变，还提取了适合于扩散相变的原子建模的参数。我们发现这些材料中化学物种之间关系的层次结构促进了有序趋势。最主要的是3D元素V与其他4D和5D元素之间的相对原子大小差异，该元素驱动B32样阶。对于不存在V的系统，订购是由价态填充的差异主导的；等电源的元素成对与低温保持弱相关，而成对与价差为单位的B2样阶。我们在VNBMOTAW中估计的订单降低过渡温度足以使我们表明该材料中的SRO可以在实验上可观察到。
Using an all-electron, first principles, Landau-type theory, we study the nature of short-range order and compositional phase stability in equiatomic refractory high entropy alloys, NbMoTa, NbMoTaW, and VNbMoTaW. We also investigate selected binary subsystems to provide insight into the physical mechanisms driving order. Our approach examines the short-range order of the solid solutions directly, infers disorder/order transitions, and also extracts parameters suitable for atomistic modelling of diffusional phase transformations. We find a hierarchy of relationships between the chemical species in these materials which promote ordering tendencies. The most dominant is a relative atomic size difference between the 3d element, V, and the other 4d and 5d elements which drives a B32-like order. For systems where V is not present, ordering is dominated by the difference in filling of valence states; pairs of elements which are isoelectronic remain weakly correlated to low temperatures, while pairs with a valence difference present B2-like order. Our estimated order-disorder transition temperature in VNbMoTaW is sufficiently high for us to suggest that SRO in this material may be experimentally observable.
