The realm of ceramic materials has seen a surge in interest directed towards high entropy disilicides due to their exceptional properties. Using the methodologies of density functional theory (DFT) and the special quasi-random structure (SQS), we have delved into the examination of structural stability and the inherent elastic properties of (NbMoTaW)Si 2 . The available experimental data and the optimized lattice parameters coincide very well. The thermodynamic stability observed in all high entropy ceramics, specifically (NbMoTaW)Si 2 disilicides, can be attributed to their negative formation enthalpies. The present results of elastic parameters show that the strength/hardness of (NbMoTaW)Si 2 are larger due to the higher bulk and shear moduli. The Vickers hardness of (NbMoTaW)Si 2 is higher than the average value of component binary metal silicide, indicating solid solution strengthening effect. The mechanical anisotropy of the (NbMoTaW)Si 2 reveals the significant difference in various directions on different crystalline planes. Conducting theoretical research holds significance in facilitating the synthesis of enhanced high entropy disilicides ceramics. Furthermore, such studies are crucial in advancing the evolution and practical utilization of high entropy materials.

Thermodynamic properties of ternary ceramic TiCN are studied by first-principles calculation combined with the Debye Einstein model, which considers the contribution of 3n−3 optical frequencies at the Γ point; Debye Grüneisen model, which treats optical frequencies as acoustic ones; and quasiharmonic approximation(QHA), which is the most prevalent method in prediction of phonon dispersion and thermal properties. No imaginary frequency shows that TiCN has dynamic stability, and negative formation energy indicates the thermodynamic stability. Particularly, TiCN has low thermal expansion coefficient, which rises quickly firstly and then gradually as temperature rises. The study of bulk modulus shows that TiCN possess excellent resistance to the volume thermal deformation. For temperature effects of thermal expansion coefficient, heat capacity and entropy, the obtained results show that Debye Einstein model are apparently closer to the QHA at low temperatures. Our present results provide guideline for exploration of thermal properties of multicomponent materials.

Multicomponent ceramics have attracted increasingly attention due to their potential applications. Employing density functional theory (DFT) and the special quasi-random structure (SQS), the structural stability and elastic characteristics of TiCNO and TiZrCNO are systematically explored in this study. The available experimental data and the optimized lattice parameters coincide very well. Both high entropy oxycarbonitrides are thermodynamically stable because the formation enthalpies are negative. According to the present results of elastic parameters, the slight expense of the strength and stiffness the ductility is improved. The increase of ductility presumably originates from the multicomponent mixing in the anion sublattice, the subsequent incorporation of Zr results in the stronger influence due to the more severe lattice distortion, as discussed in our previous study. The anisotropy of two ceramics are studied systematically, the role of the anisotropy is explored in wear/cutting applications. Then the thermodynamic properties of the two ceramics are also studied further applying Debye-Grüneisen model. Thermodynamic properties of two materials exhibit essentially similar trend as temperature rises. Because the larger lattice distortion by the subsequent addition of Zr, the bulk moduli and thermal expansion coefficient for TiZrCNO change slowly with temperature. Clearly the influences of the multianion mixing, especially the contribution from the following incorporation of Zr which leads to larger internal distortion should pay high attention. The current investigations provide valuable insight into the mechanical and thermodynamic behavior of these two multicomponent ceramics.

High-entropy perovskite ceramics have drawn widespread attention as their excellent physical properties. Herein, the high-entropy (Bi0.2Na0.2Ba0.2Sr0.2Ca0.2)TiO3 (BNBSCT) perovskite is selected as case study. The distorted structure and mechanical behavior as well as the effect of pressure are comprehensively studied through implementing first-principles calculations in conjunction with special quasi-random structure. The results reveal the atomic random distribution and size different cause serious lattice distortion within the BNBSCT structure, and the pseudo-intralayer distortion is significantly smaller than the interlayer distortion. Further studies of the mechanical properties indicate that the high-entropy BNBSCT perovskite is mechanical stable, especially larger elastic parameters imply the larger resistance against elastic deformation in comparison with Bi0.5Na0.5TiO3. Compared to the rule of mixture, the higher resistance to volume deformation and crack propagation of BNBSCT suggests the strengthening of high-entropy perovskite presumably due to lattice distortion in structure. Increasing pressure leads to decrease in lattice parameter and volume of structure, then increases the degree of lattice distortion, elastic constants and elastic moduli, as well the degree of lattice distortion. Moreover, the ductility and fracture toughness are also enhanced, though the elastic anisotropy is slightly larger. This work provides a new insight into the high-entropy perovskite under high pressure, which will contribute to the further research and application of high-entropy materials.

The thermal properties of TiCNO are studied from the Debye-Einstein model based on the first-principle in combination with the special quasi-random structural model, meanwhile the derived result is compared with those obtained by the Debye-Gruneisen model. The present results show that Debye-Einstein model is excellent in predicting the thermal properties of multicomponent random structure materials due to consideration of the 3 n - 3 optical frequencies at the Gamma point to represent the contributions of optic branches, although the DebyeGruneisen models is also effective methods for predicting the thermal properties of multicomponent materials. The two methods show that when temperature rises, the thermal expansion coefficients of TiCNO first increase rapidly and then slowly, and Debye-Einstein predicts a stronger volume sensitivity to lower temperature due to the contribution of 3 n - 3 optic frequencies at Gamma point. Although both models also predict a comparable temperature dependence of bulk modulus, the high temperature softening effect of TiCNO calculated by DebyeEinstein is gentler than that from Debye-Gruneisen, which demonstrates that the influence of optical branches cannot be negligible. With temperature increasing, the thermodynamic entropy predicted by both models increases due to the greater disorder degree of the system. Moreover, the thermodynamic entropy predicted by Debye-Einstein is larger owing to considering the optical frequencies at the Gamma point. Due to the strong coupling between the acoustic and optical phonons lying in low frequency regime, both isobaric and isochoric heat capacities predicted by Debye-Einstein are larger than those predicted by Debye-Gruneisen at low temperatures. This work is a useful reference for predicting the thermal properties of multicomponent materials.

Although severe lattice distortion is one of the core effects of multicomponent materials, accurate quantitative description is still an open issue. In this paper, density functional theory (DFT) calculations based on special quasi-random structure (SQS) are used to investigate the lattice distortion of multicomponent (TiZrHf)C and (TiZrHf)N ceramics, and the influences on structural, mechanical, electronic and thermodynamic properties. The distortion in (TiZrHf)C and (TiZrHf)N is quantified by the average atomic displacement and the bond length distribution. Our results show that the distortion in (TiZrHf)N is greater than in (TiZrHf)C. Lattice distortion can improve thermodynamic stability while enhancing ductility at the expense of strength and hardness. Moreover, the influence of lattice distortion on thermal properties is further studied, suggesting that the distortion increases the vibrational entropy due to the high-temperature softening of the lattice, thereby increasing the total entropy and thermodynamic stability of ceramics. After distortion, the thermal expansion coefficient is obviously larger and the heat capacity C V and C P also increase, especially at low temperatures. Therefore, the present study is valuable for understanding and optimization of the comprehensive properties of multicomponent ceramics by tuning the lattice distortion effect.

Multicomponent ceramics have attracted increasingly attention due to their potential applications. Employing density functional theory (DFT) and the special quasi-random structure (SQS), the structural stability and elastic characteristics of TiCNO and TiZrCNO are systematically explored in this study. The available experimental data and the optimized lattice parameters coincide very well. Both high entropy oxycarbonitrides are thermodynamically stable because the formation enthalpies are negative. According to the present results of elastic parameters, the slight expense of the strength and stiffness the ductility is improved. The increase of ductility presumably originates from the multicomponent mixing in the anion sublattice, the subsequent incorporation of Zr results in the stronger influence due to the more severe lattice distortion, as discussed in our previous study. The anisotropy of two ceramics are studied systematically, the role of the anisotropy is explored in wear/cutting applications. Then the thermodynamic properties of the two ceramics are also studied further applying Debye-Grüneisen model. Thermodynamic properties of two materials exhibit essentially similar trends as temperature rises. Because the larger lattice distortion by the subsequent addition of Zr, the bulk moduli and thermal expansion coefficient for TiZrCNO change slowly with temperature. Clearly the influences of the multianion mixing, especially the contribution from the following incorporation of Zr which leads to larger internal distortion should pay high attention. The current investigations provide valuable insight into the mechanical and thermodynamic behavior of these two multicomponent ceramics.

Multicomponent ceramics have received much attention due to the tunning physicochemical properties and the huge compositional space, while multicomponent ceramics with the mixing of multi-anion are rarely studied. In this work, the local lattice distortion and vacancy formation energy in TiCNO and TiZrCNO are systematically investigated by density functional theory calculations combining with the special quasi-random structure model. The present results show that multi-anionic mixed oxycarbonitride ceramics exhibit obvious local lattice distortion. The quantified displacive distortions of C, N, and O in TiCNO are relatively large, being in order of C < N < O, although metallic elements Ti has larger distortion than nonmetals. Within incorporative mixing of Zr in cation sublattice, the distortions of Ti, C, N, and O increase evidently, the distortion degree for nonmetal elements is still in order of C < N < O. The distortion of Ti is still the largest, whereas Zr possesses almost the smallest distortion. The electronic structure shows a close association with the degree of distortion, the larger DOS at the Fermi level corresponds to the larger distortion. The vacancy defects are further studied. Our consequences show that the vacancy formation energies of non-metal elements with large local distortions are relatively low, suggesting that the local chemical environment profoundly affects the vacancy formation energy and defect-related properties. The present study reveals the important correlation of lattice distortion with electronic structure and vacancy generation, so it is valuable to deepen the understanding of the excellent properties of multicomponent ceramics with multi-anion mixing, and develop novel multicomponent ceramics with polyanionic structures.

High-entropy perovskite oxides are novel high-entropy ceramics developing recently. In this work, the local lattice distortion, mechanical and thermodynamic properties of perovskites A(Zr0.2Sn0.2Ti0.2Hf0.2Nb0.2)O3 (A = Sr, Ba) are explored using the first principle investigation. The equilibrium lattice parameter and bulk moduli of high-entropy perovskites obtained by fitting approximately satisfy the rule of mixture of the components, while the entropy effect of component mixing is very small. The bond length distribution reveals the B-site disorder results in large local lattice distortion. The atomic displacement indicates larger average displacement of O atoms contributes mainly to the wider bond length distribution for most B-O bond. The distortion degree at B-site is naturally associated with A-site. The obtained elastic constants of high-entropy perovskites are also closed to the rule of mixing of the components. Compared with ternary SrTiO3 and BaTiO3 perovskites, B-site mixing for high-entropy perovskites enhances their toughness at expense of strength and stiffness, showing the elastic moduli can be modified and adjusted through multi-component design strategy. Relevant thermodynamic property reveals the B-site disorder is benefit to improve the resistance to softening and suppress volume expansion at high temperature. Electronic structures show the insulator–metal transition takes place, also uncover that the interaction of B-O bond is stronger.

The intrinsic mechanical properties of NbTaTiZr and NbTaTiZrX (X]Mo, W) are studied by using a firstprinciples calculation in combination with special quasi-random structure. For NbTaTiZr RHEA, the ideal tensile strength (ITS) and compressive strength (ICS) along [001] direction is respectively calculated to be 5.64 GPa and -18.4Gpa at the strain 11% and -20%. For shear loading along (211)[111] slip system, the ideal shear strength (ISS) is 3.03 GPa as the strain is about 20%. With addition of Mo into NbTaTiZr, the ITS, ICS and ISS respectively increase up to 9.7, -19.3 and 4.73 GPa, and the addition of W enhances the ITS, ICS and ISS up to 10.5, -21.1 and 5.12 GPa, respectively. Hence addition of Mo or W can significantly improve the ideal strength, especially stronger impact of W element. The calculated elastic moduli E[001] and G[111] are in reasonable agreement with the initial slope of the stress-strain relationship. The derived dimensionless ITS and ISS from first-principle calculations is underestimated the ideal strength in comparison with the prediction by the universal empirical model. Then the microcosmic mechanism is further studied by examination of the detailed bond length variation of three HEAs during the corresponding deformation. Near the critical strain under of tension and shear, the slower descend of stress originates from the gradual breakage of atomic bonds, while the compressive stress decreases rapidly owing to all bond fracturing almost simultaneously. Finally, the ideal strength of three HEAs is further analyzed from electronic structure.

High-entropy ceramics with multi-cationic and -anionic structures have large composition space and adjustable properties, although their potential properties are still unclear. For newly developed hexagonal closed-packed high-entropy alumino-silicides (MoNbTaV)(AlSi)2, the mechanical properties are investigated by ab initio calculation, and the influence of Al in anion sublattice is discussed emphatically. Taking MSi2 (M = Mo, Nb, Ta, V) as reference, the influence of adding Al in anion sublattice on mechanical properties of MSi2 (M = Mo, Nb, Ta, V) is firstly studied. Our results show that the addition of Al in anion sublattice strongly reduces the single-crystal elastic constants and the polycrystalline elastic moduli, which results in a transition from brittleness to ductility of M(AlSi)2 (M = Nb, Ta, V, except M = Mo) and (MoNbTaV)(AlSi)2 at the expense of strength and hardness. Moreover, the anisotropy is larger, presumably because Al element is different from Si element. The influence of the following cation mixing is not as dramatic as the anion mixing, and approximately follows the role of mixture, similar to the previous investigations. The further studied electronic structure of (MoNbTaV)(AlSi)2 gains more insight into bonding characteristics and reveals the underlying mechanism of mechanical properties. Our results are benefit to inspect mechanical performance of multi-component alloys by tuning elemental composition and sublattice mixing.

Novel high-entropy ceramics have been rapidly developing and exhibiting excellent properties. In this paper, the structural distortion and the influence on mechanical and thermodynamic properties of (HfZrTaNbTi)C, (HfZrTaNbTi)N and (HfZrTaNbTi)(NC) are systematically studied by employing density functional theory in conjunction with special quasi-random structure (SQS). Our results show that lattice distortion enhances the structural stability of these high-entropy ceramics by lowering the formation and mixing enthalpy. The local lattice distortion in considered ceramics is further quantified in terms of constituent atoms displacement and bond length distribution, suggesting that (HfZrTaNbTi)C and (HfZrTaNbTi)N possess the smallest and largest distortion, respectively. While the distortion in anion and cation mixed (HfZrTaNbTi)(NC) is intermediate. The elastic properties illustrate that the distortion improved the ductility of high-entropy ceramics at the slight expense of strength and stiffness. The electronic structures show that (HfZrTaNbTi)C has the strongest covalent bonds and (HfNbTaTiZr)N possesses a stronger ionic character. After distortion, the DOS at the Fermi level for the three ceramics is reduced and the charge density is significantly enhanced, revealing the underlying mechanism for stability improvement. Combining the Debye-Grüneisen model, the thermodynamic properties and the influence of lattice distortion are further studied. It is found that lattice distortion improves thermal expansion and heat storage capacity. Simultaneously, the distortion also increases the entropy of ceramics, thereby enhancing the stability in high-temperature environments. This paper provides a valuable reference for understanding crucial properties and designing promising multi-cation and anion mixed high-entropy ceramics by revealing the vital role of lattice distortion.

采用特殊准随机结构(Special Quasi-random Structure,SQS)处理高熵合金固溶体的化学无序性,并基于密度泛函理论研究了 具有面心立方(Face-centered Cubic,FCC)和密排六方(Hexagonal Close-packed,HCP)结构的 Al20Li20Mg10Sc20Ti30 高熵合金的结构稳定性和热力学性质.理论得到的两个相的晶格常数与实验测量值符合较好.两相中,由于HCP相具有较FCC相略大的体模量,因而其具有较好的抗压缩性能.由于计算得到的两个相在0K时的形成焓都为小的正值,因而两个相都为热力学亚稳结构.采用Debye-Grüneisen模型研究了不同温度下两个相的热力学性质,结果表明两个相的体模量随温度的上升表现出缓慢的下降趋势,且HCP相的体模量大于FCC相,而FCC相具有更大的体积热膨胀系数.研究了两个相的熵(包括振动部分的贡献和电子部分的贡献)随温度的变化,结果表明在研究的温度范围内,HCP相比FCC相具有更大的熵,且两个相的熵的主要来源都为振动部分的贡献.

The evolution of structural, elastic, and electronic properties of high entropy carbide (HfTaZrTi)C and (HfTaZrNb)C under high pressure have been studied within the framework of density functional theory (DFT) in conjunction with special quasirandom structures. With increasing pressure, lattice constants of high entropy carbides (HfTaZrTi)C and (HfTaZrNb)C gradually decrease, so volumes shrink, and densities gradually increase. Under high pressure up to 200 GPa, elastic stiffness coefficients for both carbides are almost linearly hardened and meet the elastic stability criteria. With increasing pressure, elastic moduli and Debye temperature of both high entropy carbides (HfTaZrTi)C and (HfTaZrNb)C increase, while theoretical Vickers hardness decreases, although Vickers hardness of (HfTaZrNb)C is always higher than (HfTaZrTi)C in the whole pressure. The ductility of (HfTaZrTi)C and (HfTaZrNb)C is improved under pressure, and brittle-ductile transition occurs at about 50 and 60 GPa, respectively. The electronic structure demonstrates that, with increasing pressure, covalent bonds between transition metal atoms and carbon atoms are strengthened, accompanying delocalization. This effect is responsible for high values of bulk modulus and shear modulus under pressure and enhanced ductility. The ionic bonds of both high entropy carbides weaken with increasing pressure, and (HfTaZrTi)C is affected more strongly by the pressure.

Ternary alloy ZrHfTi is a novel hexagonal close-packed medium entropy material. As a fundamental parameter for understanding the deformation behavior and mechanical property especially ductility, the stacking fault energy (SFE) of basal plane for ZrHfTi alloy has been studied. Unlike the case of CrCoNi-based alloys, the derived SFEs for intrinsic and twin-like stacking faults of alloy ZrHfTi are relatively high. From the evolution features of stacking fault energies from unitary to binary and ternary materials, the SFEs of studied alloys are intermediate between component materials due to merely mixing effect. Because the SFEs of the constituent elements are relatively large, the SFEs of multicomponent alloys are not necessarily small. The SFE of ZrHfTi is obviously affected by alloying of constituent elements with strong structural propensity. Based on the generalized stacking fault energy, mechanical properties and deformation characteristics are further studied. Our results demonstrate that ZrHfTi has good ductility and high yield strength, and deformation twin in ZrHfTi is also very possible based on the twinning criteria. The research of this paper is beneficial for the design and development of more valuable high-performance multicomponent alloys.

The intrinsic mechanical properties of novel hexagonal high entropy alloys (HEAs) Hf0.25Ti0.25Zr0.25Sc0.25−xAlx (x ≤ 15%) have been studied using first-principles theory based on special quasi-random structure, and influence of Al content is stressed. The derived formation enthalpy and elastic constants indicate the thermodynamical and mechanical stability of the studied alloys. With substitution of Al for Sc, bulk modulus, shear modulus and Young's modulus tend to decrease, while HEAs become more ductile. The estimated elastic anisotropies of alloys show an ascending trend with increasing Al content, and the shear and tensile Young's moduli along several typical directions have been obtained for the studied HCP crystal. Furthermore, the studied ideal strength of HCP HEAs suggest that the ideal tensile strength (ITS) of HEAs occurs in [112̅0] direction, and decreases from 5.34 GPa to 3.80 GPa with increasing Al content for x goes from 0.00 to 0.15, whereas corresponding critical tensile strain increases from 0.07 to 0.08. The ideal shear strength (ISS) of HEAs takes place in (101̅0)< 112̅0 > shear system. With increasing Al content for x goes from 0.00 to 0.15, the ISS decrease from 3.71 GPa to 2.46 GPa, the corresponding critical shear strains increase also from 0.10 to 0.11. So HEAs are more ductile as increasing Al concentration at expense of both ITS and ISS. It is worth noting that the initial slopes of tensile and shear stress–strain are in good agreement with the tensile and shear modulus from elastic parameter, also exhibiting descending trend with Al content. The critical resolved shear stresses (CRSS) estimated from the ITS for HEAs is smaller than the corresponding ISS, suggesting that slip is preference to cleavage. The shearability and half-width of the dislocation are also evaluated and discussed. Furthermore, the detailed electronic structure in bond length evolution is further studied, from feature of the Al-M atom pairs due to addition of Al element, the mechanism for enhancement of ductility for HfTiZrSc1−xAlx is uncovered, all of these provide more details for more adequate understanding deeply the intrinsic mechanism of mechanical properties of alloys HfTiZrSc1−xAlx.

High-entropy ceramics have recently attracted considerable attentions because of excellent combination of exceptional properties. In this work, the temperature dependent elastic properties of (ZrTaNbTi)C have been systematically studied from the density functional perturbation theory combined with self-consistent quasiharmonic approximation. High entropy ceramic (ZrTaNbTi)C is thermodynamically stable due to the negative formation enthalpy, and is also mechanically stable from the obtained elastic properties. The phonon dispersion relation computed at equilibrium volume contains no imaginary-frequency, implying the dynamical stability. At 0 K, (ZrTaNbTi)C possesses evidently high elastic moduli and hardness. The calculated electronic density of state and Bader charge at 0 K and 2000 K show that (ZrTaNbTi)C have covalent characteristics accompanied by ionic feature while the covalency decreases and the ionicity increases as temperature increases. The temperaturedependent elastic properties show that (ZrTaNbTi)C is mechanically stable in temperature range studied, and remains high strength and hardness at high temperature due to the slight softening of strong covalent bonding. Poisson's ratio, Pugh's ratio and Cauchy pressure suggest the higher brittle-ductile transformation trend as the temperature increases. Moreover, (ZrTaNbTi)C shows less anisotropy at higher temperature from the Zener index AZ and three-dimensional projections, being beneficial to reduce cracking and improve durability. The present study provides more insight into the high temperature behavior of mechanical properties, would be valuable for understanding and design of high-temperature properties of high entropy carbide ceramics.

The finite temperature elastic properties of non-equiatomic refractory high-entropy alloys (RHEAs) HfNbZrTa1−xTix 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, HfNbZrTa1−xTix 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 HfNbZrTa1−xTix 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.

The stacking fault energy (SFE) is fundamental to understand the mechanical behavior of materials, and is also closely related to the structural phase transition. In present work, the generalized stacking fault energies of basal plane for novel hexagonal close-packed high-entropy alloys Hf0.25Ti0.25Zr0.25Sc0.25-xAlx (x < 15%) are studied using density functional theory and special quasi-random structure for modeling the chemical disorder, and the effect of aluminum is emphasized. With increase of Al content, the lattice constant a decreases, while c/a increases. Especially, the addition of Al is favorable to reduce the unstable and stable stacking fault energies of the studied alloys. The lower SFE further improves the ductility, creep resistance and yield strength of materials. Moreover, with replacement of Sc by Al, lower gamma(ISF)/gamma(USF) ratio of stable intrinsic SFE (gamma(ISF)) to unstable intrinsic SFE (gamma(USF)) and higher gamma(USF)/gamma(UTF) ratio of unstable intrinsic SFE to unstable twin-like SFE (gamma(UTF)) suggest that although both the dislocation decomposition and twinning are favored, the dislocation decomposition is still predominant due to stronger decrease of gamma(ISF)/gamma(USF). Furthermore, the much larger unstable twin-like SFE gamma(UTF) than the unstable intrinsic SFE gamma(USF) also indicates that the main deformation mechanism in Hf0.25Ti0.25Zr0.25Sc0.25-xAlx (x < 15%) may be dislocation-mediated slip. The further calculated electronic structure shows that replacement of Sc by Al enhances the covalent bonding of high-entropy alloys Hf0.25Ti0.25Zr0.25Sc0.25-xAlx (x < 15%), and reduces the energy difference during the sliding process, thus lower the stacking fault energy. The present investigation is very valuable and helpful for understanding and developing of high performance of novel hexagonal close packed high-entropy alloys. (C) 2021 Elsevier B.V. All rights reserved.

The unique mechanical properties and local lattice distortion (LLD) for hexagonal close‐packed (HCP) multiple principal element alloys (MPEAs) are very rarely studied so far. Employing density functional theory calculation based on special quasirandom structure, this work studies the influences of LLD on elastic properties for both novel hexagonal TiZrHf(Sc) MPEAs. Compared to the pristine structures, the lattice stability of distorted random structures is improved evidently. Moreover, LLD obviously lessens the shear elastic properties, which may be an ubiquitous phenomenon irrespective of the lattice types of MPEAs. These results also uncover the apparent improvement in malleable behavior and shear anisotropy for HCP MPEAs. So, the influence of LLD on elastic properties for HCP MPEAs is profound. The degree of LLD is further studied via the standard deviation of near‐neighbor (NN) and next NN bond length distributions as an effective indicator of LLD. More significant distortion uncovered in TiZrHf alloy corresponds consistently to the stronger effects of LLD in TiZrHf alloy. Bader's charge and charge density distribution also demonstrate the underlying impact on LLD for both HCP MPEAs, so electronic nature is a significant factor for LLD. The present study provides guideline for designing mechanical properties of TiZrHf‐based HCP MPEAs engineering materials.