The finite temperature elastic properties of non-equiatomic refractory high-entropy alloys (RHEAs) HfNbZrTa_1−xTi_x are investigated using the exact muffin‑tin orbitals method in combination with coherent potential approximation and Debye-Grüneisen model, especially the effect of Ta and Ti addition is emphasized. Taking HfNbZr as a reference, the lattice constants decrease when alloying with Ta, and continue to decline slightly with replacement of Ta by Ti. Estimating from calculated elastic parameters, mere Ta addition leads to the high strength and stiffness accompanying evident lowering of ductility, while sole Ti addition brings about the high ductility at the expense of reducing strength and hardness. With substitution of Ti for Ta, HfNbZrTa_1−xTi_x alloys achieve a relatively high ductility accompanied a gentle decline in high strength and hardness. As temperature increases, although the obtained single-elastic and polycrystalline elastic parameters exhibit decreasing trend, the anti-softening ability is enhanced with substitution of Ti for Ta, and HfNbZrTa_1−xTi_x alloys remain an overall good combination of strength and ductility at high temperature. The proper strength-ductility trade-off can be gained by tuning Ti/Ta ratio, which is beneficial for designing the high temperature mechanical properties of alloy.

使用精确的松饼-锡轨道方法，结合相干势近似和Debye-Grüneisen模型，研究了非等原子质难熔高熵合金HfNbZrTa _1-x Ti _x的有限温度弹性并强调了钛的添加。以HfNbZr为参考，当与Ta合金化时，晶格常数减小，而在用Ti代替Ta时，晶格常数继续略微下降。从计算的弹性参数估计，仅添加Ta会导致高强度和刚度，同时会明显降低延展性，而仅添加Ti会带来高延展性，但会降低强度和硬度。用Ti代替Ta时，HfNbZrTa _1-x Ti_x合金具有较高的延展性，并伴随着高强度和硬度的缓慢下降。随着温度的升高，尽管获得的单弹性和多晶弹性参数呈现下降趋势，但是通过用Ti代替Ta可以增强抗软化能力，并且HfNbZrTa _1-x Ti _x合金仍在强度和延展性方面保持了良好的结合。高温。通过调节Ti / Ta比可以得到适当的强度-延展性的折衷，这有利于设计合金的高温力学性能。