Ideal simple shear strengths of two HfNbTaTi-based quinary refractory multi-principal element alloys

Abstract

Atomistic simulations are employed to investigate chemical short-range ordering in two body-centered cubic refractory multi-principal element alloys, HfMoNbTaTi and HfNbTaTiZr, and its influence on their ideal simple shear strengths. Both the alias and affine shear strengths are analyzed on the {110} and {112} planes in the two opposing [Formula: see text] directions. In both quinary alloys, local ordering of NbNb, TaTa, HfNb, HfTa, and NbTa is preferred as the annealing temperature decreases from 900 to 300 K. The pair that achieves the highest degree of local ordering is TiTi in HfMoNbTaTi and HfTi in HfNbTaTiZr. Subject to the affine shear, these alloys yield by first phase transformation at the most likely pairs followed by deformation twinning at those sites.

Nanoindentation into a bcc high-entropy HfNbTaTiZr alloy—an atomistic study of the effect of short-range order

“…The interatomic potential is chosen as an embedded-atom-method-type potential 9 based on previous work on the construction of alloy potentials 35 , 36 . Xu et al 9 implemented this potential in order to correctly describe the short-range order and the resulting shear strengths in HfNbTaTi-based quinary refractory multi-principal element alloys.…”

“…The interatomic potential is chosen as an embedded-atom-method-type potential 9 based on previous work on the construction of alloy potentials 35 , 36 . Xu et al 9 implemented this potential in order to correctly describe the short-range order and the resulting shear strengths in HfNbTaTi-based quinary refractory multi-principal element alloys. We note that an alternative potential for this material is available 37 , but our calculation of elastic constants using that potential does not match experimental results as well as the potential used here, as mentioned by Ref.…”

“…Among them, the equiatomic HfNbTaTiZr alloy has become one of the best investigated examples 3 ; it is also known as the Senkov alloy 8 . Thus, Xu et al 9 directly model the shear strength of the HfNbTaTiZr alloy and observe failure by a bcc-to-fcc phase transformation initiating in HfTi rich regions. Liang et al 10 study how variable fractions of Hf and Ta in HfNbTaTiZr alloys affect the tensile strength.…”

“…In the present paper, we study the plasticity induced during nanoindentation in the Senkov HfNbTaTiZr high-entropy alloy. Because of the possible influence of chemical short-range order discussed recently 9 , both a random alloy and an alloy with chemical short-range order are considered. In addition, we compare to the well understood case of indentation into an elementary Ta crystal 29 – 31 , allowing us to highlight the differences in plastic behavior.…”

Comparing interatomic potentials in calculating basic structural parameters and Peierls stress in tungsten-based random binary alloys

“…For example, face-centered cubic (fcc) MPEAs have shown high damage tolerance and strength at cryogenic temperatures [9,10], while body-centered cubic (bcc) MPEAs possess high melting points and exceptional mechanical strength at elevated temperatures [11,12]. Due to the infinite possibility of compositions and their ratios, predicting the properties of MPEAs is difficult [13,14]. So it is useful to first study binary systems to obtain the characteristic traits of constituent elements and their combinations [15].…”