Exploring high corrosion-resistant refractory high-entropy alloy via a combined experimental and simulation study.pdf
npj | materials degradation Article Published in partnership with CSCP and USTB https://doi.org/10.1038/s41529-024-00495-1 Exploring high corrosion-resistant refractory high-entropy alloy via a combined experimental and simulation study Check for updates Xinpeng Zhao1, Haiyou Huang1,2 , Yanjing Su1,2, Lijie Qiao1,2 & Yu Yan 1,2 Refractory high-entropy alloys (HEAs) have attracted considerable attention due to their stable phase structure and excellent high-temperature properties. In this work, we performed ﬁrst-principles calculations, coupled with experiments, to explore HEAs with high corrosion resistance. The results revealed that TiNbTa-based HEAs exhibited a lower tendency for corrosion. However, the appearance of local chemical ﬂuctuations (LCFs) increased the corrosion tendency of TiNbTa-based HEAs. Comprehensive SHapley Additive exPlanations analyses uncovered that in a sample with conﬁgurational LCFs, the atomic order near the surface was altered. Therefore, corrosion behavior was affected. Based on experiments, the annealed samples exhibited typical chemical segregation and declined corrosion resistance. High-entropy alloys (HEAs) have attracted increasing attention due to their disordered atomic structure, exhibiting numerous desirable properties that cannot be achievable by traditional alloys1–3. The elevated conﬁgurational entropy in HEAs plays a pivotal role in stabilizing the formation of simple solid solution phases while impeding the development of detrimental intermetallic compounds4,5. The demand for new structural alloys with commendable mechanical properties and excellent corrosion resistance is particularly pronounced in application sectors such as aerospace, clean power,and biomedicalindustries.RefractoryHEAs,composed of refractory metals, generally exhibit superior mechanical properties and resistance to general corrosion6–8, presenting promising prospects for diverse applica- tions. Several refractory HEAs have demonstrated signiﬁcant potential due to their remarkable strength. For example, during room temperature deformation, HEAs such as NbMoTaW and VNbMoTaW alloys have shown high yield stress values of 1058 and 1246 MPa, respectively9. Recent studies have shown that exploration of chemical heterogeneity during the heat treatment process, such as short-range order and local chemical ﬂuc- tuations (LCFs), has opened up a new avenue for the development of high- strength HEAs10–12. A recent study reported evidence of consequential effects in NiCoCr, with the yield strength further increasing by 76% after annealing at 2073 K for 24 h13. When the annealing duration of the TiZrHfNb alloy at 673 K was prolonged to 40 h, the hardness increased by 25%14. Meanwhile, LCFs could lower the conﬁgurational entropy from its maximum value, corresponding to a random alloy, and change the expressions for free energy. LCFs was also found to decrease the enthalpy of the system, inﬂuencing defect energetics and potentially affecting physical properties. Consequently, chemical heterogeneity may affect the corrosion properties of HEAs. It is well known that chemical heterogeneity is the primary cause of localized galvanic corrosion. Compared with a chemically homogeneous single-phase solid solution, the occurrence of elemental segregation beha- vior leads to the formation of different electrochemical potential regions within the alloy, which undoubtedly signiﬁcantly increases its sensitivity to corrosion15. However, it is worth noting that certain chemical hetero- geneities can enhance the corrosion resistance of an alloy. Taking the NiCoVAlx alloy as an example, an increase in the content of Al leads to a higher proportion of the B2 phase, which has a higher Volta potential, thereby improving the overall corrosion resistance of the alloy16. Since the emergence of LCFs is widely considered to be the origin of elemental segregation17, it is particularly important to conduct in-depth research on the impact of LCFs on the corrosion performance of alloys. However, only a few studies have reported on the corrosion behavior of refractory HEAs, with a signiﬁcant gap in research on the effect of LCFs on corrosion properties. Equiatomic TiZr(Hf, Ta, Nb) medium entropy alloys have been developed to achieve superiorcorrosion resistance compared with pure Ti18. MoNbTaTiZr HEAs have exhibited a distinctive combination of friction 1Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing, 100083, China. 2Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China. e-mail: huanghy@mater.ustb.edu.cn; yanyu@ustb.edu.cn npj Materials Degradation |   (2024) 8:77  1 1234567890():,; 1234567890():,; and corrosion resistance, outstanding mechanical properties, and bio- compatibility, positioning them as potential bioimplants19. Recently, non- equiatomic TiNbTaZrMo HEAs with good biocompatibility have been designed20. Consequently, non-equiatomic HEAs, with extensive and unexplored composition spaces, present an opportunity to obtain highly corrosion-resistant alloys. However, systematic research on the effect of various elements and the corrosion resistance of refractory HEAs has remained insufﬁcient, creating a bottleneck in designing corrosion-resistant HEAs.Theabilityto freelyadjustalloycompositioninHEAs,resultinginan enormous composition space, signiﬁcantly complicates the determination of corrosion resistance of new materials. Therefore, an efﬁcient and rapid forecasting method for corrosion resistance is urgently needed to guide experimental synthesis. The Monte Carlo (MC) molecular dynamics (MD) simulation method has proven useful for chemical heterogeneity investigations21,22. However, limitationsinpotentialavailabilitymakeitchallengingtosimulateinvarious composition models using the MD/MC method. Reliable interatomic potentials are considered essential for MD simulations23. However, only a limited numberof potentialshave beendeveloped forHEAs, due to the brief history of HEAs and the substantial workload required to develop multi- elemental interatomic potentials. Density functional theory (DFT) has emerged as a promising solution for addressing this challenge, as it can handle multi-elemental systems24,25. The effect of chemical heterogeneity on the mechanical properties of HEAs has been extensively investigated via the DFT/MC method26,27, indicating that it will have a signiﬁcant effect on critical parameters, notably the stacking-fault energy26 and dislocation mobility27. In this work, we elucidated the chemical heterogeneity and corrosion resistance of Ti(Nb,Zr)(Zr,Nb,Ta)(Ta,Ha,V,Cr,Mo,W) quaternary refrac- toryHEAsthroughacombinationofMCsimulationsand experiments.The effectofLCFsonthecorrosionbehaviorofrefractoryHEAswasinvestigated using the DFT/MC method to determine the reasons for corrosion resis- tance variations. Results and discussion Generation of appropriate surface structures The calculated formation energies for the (110) surfaces of the bcc and (111) surfaces of the fcc in 16 refractory HEAs are presented in Fig. 1, namely TiNbTaCr (TNTC), TiNbTaHf (TNTH), TiNbTaMo (TNTM), TiNbTaV (TNTV), TiNbTaW (TNTW), TiZrNbCr (TZNC), TiZrNbHf (TZNH), TiZrNbMo (TZNM), TiZrNbTa (TZNT), TiZrNbV (TZNV), TiZrNbW (TZNW), TiZrTaCr (TZTC), TiZrTaHf (TZTH), TiZrTaMo (TZTM), TiZrTaV (TZTV), and TiZrTaW (TZTW). A substantial number of atoms in the bcc and fcc slab structures had been observed, and the calculated formation energies highlighted the stability of the generated structures. The bcc structure, with the lowest formation energy, was selected for corrosion behavior studies. Following electronic self-consistent calculations, the magnetic character of the initially set magnetic alloying element Cr per- sisted, while other systems became non-magnetic. Therefore, in subsequent calculations, only the magnetism of the alloying element Cr was considered. To computationally examine the effect of local chemical order on the corrosion behavior of these refractory HEAs, realistic models in the system were developed. Previous studies employed a systematic cluster expansion approach to explore local chemical heterogeneity in the TiZrNb, TiZrHfNb, and TiZrHfNbTa bcc refractory HEAs28. Although these studies indicated that LCFs were expected to affect the mechanical properties, no systematic study has been conducted encompassing all refractory elements to explain the effect on the corrosion behavior of refractory HEAs. In this work, the DFT/MC method was employed to develop models for refractory HEAs solid solutions with varying degrees of LCFs. The most signiﬁcant trends in potentialenergychangebasedontheDFT-basedMCsimulationsareshown in Fig. 2a. Despite the relatively small number of swap trials per atom compared with classical MC simulations, the potential energy curves appeared to converge. The appearance of LCFs reduced the free energy primarily by lowering the formation energy with a range from 38 to 447 meV per atom. Simul- taneously, it had a signiﬁcant effect on the microstructure of the alloy. To describe the trends in local chemical ordering obtained by the MC simu- lations, we employed Warren-Cowley parameter (WCP) to characterize. A positive value of WCP indicated that the atomic pair was unfavorable, while a negative value indicated that the atomic pair was favorable. The resulting indicatedthesegregationofdifferentelements,withsomeelementsshowing signiﬁcantly stronger segregation than others. This tendency was captured by the WCP in Fig. 2b–d, where some elements had a propensity to form clusters, and others favored neighbors of other types. As shown in Fig. 2b, therewasastrongtendencytoformX-Tapairs(WCP < 0)inTiNbTa-based HEAs, except for Hf. By contrast, the Ti-X and X-X pairs were unfavorable (WCP > 0). However, the results showed that the Ti-Hf pair was favorable (WCP=−0.71),whiletheHf-Tapairwasunfavorable(WCP = 0.44),which was attributed to the large atomic size of Hf, leading to segregation on the surface. Similar trends were also observed for the TiZrNb-based HEAs, where the Nb-X pair was favored (WCP < 0), and Zr-Cr, Zr-Mo, Zr-V, and Ti-Hf exhibited a strong trend to form pairs. Preferred atomic pairings betweenX-Ta,Ti-Hf,Zr-Cr,Zr-Mo,andZr-VwereobservedintheTiZrTa- based HEAs as the WCP values were negative, conﬁrming the energetic preference in the refractory alloys. Therefore, this result provided another perspective for understanding the corrosion behavior of refractory HEAs. Thus, the experimental identiﬁcation of chemical heterogeneity in the refractory HEAs requires further investigation. Work function effects of refractory HEAs A high surface work function, derived from the electron potential energy, typically indicates a high corrosion potential and corrosion resistance for materials according to traditional theory29–31. For refractory HEAs with random compositional disorder, the calculated values of the work function are shown in Fig. 3a. The calculated work function values for different samples displayed a large range,spanning from 3.95 to 4.57 eV. Notably, the group of TiNbTa-based refractory HEAs exhibited a higher work function, suggesting potentially better corrosion resistance compared to the other two groups. The work function in the refractory HEAs could be quantitatively correlated with the degree of LCFs, reﬂected by the total nonproportional number of local atomic pairs, WCPsum, as shown in Fig. 3b–d. For most HEAs, the work function was smaller in the more ordered sample, and a lower work function implied a higher probability of electron loss and a Fig. 1 | Calculated formation energies for the (110) surfaces of the bcc and (111) surfaces of the fcc in various refractory HEAs. The squares and diamonds repre- sent the formation energies, with the former excluding and the latter including the initial magnetic properties of the elements in considered. The red line and the blue line respectively denote the bcc and fcc structures of the various refractory HEAs. https://doi.org/10.1038/s41529-024-00495-1 Article npj Materials Degradation |   (2024) 8:77  2 auxiliary electrode. The samples were mounted in contact with copper wire embedded in epoxy resin, then polished, degreased in alcohol, cleaned, and dried in warm air. Prior to the potentiodynamic polarization scan tests, cathodicpre-polarizationat−1.0VSCEfor600 swasappliedtospontaneously remove the air-formed oxides. Subsequently, the open circuit potential was measured for 30 min to ensure a steady-state potential. Potentiodynamic polarization curves were obtained ata scanning rate of 1 mV/s from an initial potential of −0.6 VSCE versus Ecorr to a ﬁnal potential of 1 VSCE. A transmission electron microscope (TEM, FEI Talos F200X) equip- ped with an energy dispersive spectrometer (EDS) was used to further analyze the nanoscale microstructure in the HEAs. Data availability The raw/processed data required to reproduce these ﬁndings can be obtained by contacting the corresponding author. Code availability Thecoderequiredtoreproducetheseﬁndingscanbeobtainedbycontacting the corresponding author. Received: 7 May 2024; Accepted: 7 July 2024; References 1. Ma,C. L., Li, J. G., Tan, Y., Tanaka, R.& Hanada, S. Microstructureand mechanical properties of Nb/Nb5Si3 in situ composites in Nb–Mo–Si and Nb–W–Si systems. Mater. Sci. Eng. A 386, 375–383 (2004). 2. Miracle, D. B. & Senkov, O. N. A critical review of high entropy alloys and related concepts. Acta Mater. 122, 448–511 (2017). 3. Li, T. et al. CALPHAD-aided design for superior thermal stability and mechanical behavior in a TiZrHfNb refractory high-entropy alloy. Acta Mater. 246, 118728 (2023). 4. DiStefano, J. R. & Hendricks, J. W. Oxidation rates of niobium and tantalum alloys at low pressures. Oxid. Met. 41, 365–376 (1994). 5. Kim, B. G., Kim, G. M. & Kim, C. J. Oxidation behavior of TiAl-X (X= Cr, V, Si, Mo or Nb) intermetallics at elevated temperature. Scr. Metall. Mater. 33, 1117–1125 (1995). 6. Senkov, O. N., Miracle, D. B., Chaput, K. J. & Couzinie, J. P. Development and exploration of refractory high entropy alloys—A review. J. Mater. Res. 33, 3092–3128 (2018). 7. Zhou, Q. et al. Corrosion behavior of Hf0.5Nb0.5Ta0.5Ti1.5Zr refractory high-entropy in aqueous chloride solutions. Electrochem. Commun. 98, 63–68 (2019). 8. Yang, W., Liu, Y., Pang, S., Liaw, P. K. & Zhang, T. Bio-corrosion behavior and in vitro biocompatibility of equimolar TiZrHfNbTa high- entropy alloy. Intermetallics 124, 106845 (2020). 9. Senkov, O. N., Wilks, G. B., Scott, J. M. & Miracle, D. B. Mechanical properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 refractory high entropy alloys. Intermetallics 19, 698–706 (2011). 10. Lei, Z. et al. Enhanced strength and ductility in a high-entropy alloy via ordered oxygen complexes. Nature 563, 546–550 (2018). 11. Schuh,B. et al. Thermodynamic instability of a nanocrystalline, single- phase TiZrNbHfTa alloy and its impact on the mechanical properties. Acta Mater. 142, 201–212 (2018). 12. Huang, X. et al. Atomistic simulation of chemical short-range order in HfNbTaZr high entropy alloy based on a newly-developed interatomic potential. Mater. Des. 202, 109560 (2021). 13. Maiti, S. & Steurer, W. Structural-disorder and its effect on mechanical properties in single-phase TaNbHfZr high-entropy alloy. Acta Mater. 106, 87–97 (2016). 14. Wang, S. D. et al. Chemical short-range ordering and its strengthening effect in refractory high-entropy alloys. Phys. Rev. B 103, 104107 (2021). 15. Zhang, J. Y. et al. High-entropy alloys: a critical review of aqueous corrosion behavior and mechanisms. High. Entropy Alloy. Mater. 1, 1–65 (2023). 16. Pan, Z. et al. Tailoring microstructure and corrosion behavior of CoNiVAlx medium entropy alloys via Al addition. Corros. Sci. 207, 110570 (2022). 17. Leong, Z., Ramamurty, U. & Tan, T. L. Microstructural and compositional design principles for Mo-V-Nb-Ti-Zr multi-principal element alloys: a high-throughput ﬁrst-principles study. Acta Mater. 213, 116958 (2021). 18. Wang, Z. et al. Corrosion and tribocorrosion behavior of equiatomic refractory medium entropy TiZr(Hf, Ta, Nb) alloys in chloride solutions. Corros. Sci. 199, 110166 (2022). 19. Shittu, J. et al. Biocompatible high entropy alloys with excellent degradation resistance in a simulated physiological environment. ACS Appl. Bio. Mater. 3, 8890–8900 (2020). Fig. 10 | TEM results of the Ti-rich regions in the annealed TiNbTaMo. a High magniﬁcation EDS element distribution mapping; b TEM dark-ﬁeld image showing the precipitates; c concentration proﬁles along the LS1, as depicted in panel b; and d high-resolution TEM image of the precipitate region, and associated FFT images for the R1 and R2 regions. https://doi.org/10.1038/s41529-024-00495-1 Article npj Materials Degradation |   (2024) 8:77  9 20. Hori, T., Nagase, T., Todai, M., Matsugaki, A. & Nakano, T. Development of non-equiatomic Ti-Nb-Ta-Zr-Mo high-entropy alloys for metallic biomaterials. Scr. Mater. 172, 83–87 (2019). 21. Ding, Q. et al. Tuning element distribution, structure and properties by composition in high-entropy alloys. Nature 574, 223–227 (2019). 22. Chen, S. et al. Simultaneously enhancing the ultimate strength and ductility of high-entropy alloys via short-range ordering. Nat. Commun. 12, 4953 (2021). 23. Cao, G. et al. Liquid metal for high-entropy alloy nanoparticles synthesis. Nature 619, 1–5 (2023). 24. Tamm, A., Aabloo, A., Klintenberg, M., Stocks, M. & Caro, A. Atomic- scale properties of Ni-based FCC ternary, and quaternary alloys. Acta Mater. 99, 307–312 (2015). 25. Yin, S., Ding, J., Asta, M. & Ritchie, R. O. Ab initio modeling of the energy landscapefor screwdislocationsin body-centered cubic high- entropy alloys. npj Comput. Mater. 6, 110 (2020). 26. Ding, J., Yu, Q., Asta, M. & Ritchie, R. O. Tunable stacking fault energies by tailoring local chemical order in CrCoNi medium-entropy alloys. Proc. Natl Acad. Sci. 115, 8919–8924 (2018). 27. Li, Q. J., Sheng, H. & Ma, E. Strengthening in multi-principal element alloys with local-chemical-order roughened dislocation pathways. Nat. Commun. 10, 3563 (2019). 28. Xun, K. et al. Local chemical inhomogeneities in TiZrNb-based refractory high-entropy alloys. J. Mater. Sci. Technol. 135, 221–230 (2023). 29. Guillaumin, V., Schmutz, P. & Frankel, G. S. Characterization of corrosion interfaces by the scanning Kelvin probe force microscopy technique. J. Electrochem. Soc. 148, B163 (2001). 30. Li, W. & Li, D. Y. Variations of work function and corrosion behaviors of deformed copper surfaces. Appl. Surf. Sci. 240, 388–395 (2005). 31. Tao, S. & Li, D. Y. Nanocrystallization effect on the surface electron work function of copper and its corrosionbehaviour.Philos. Mag. Lett. 88, 137–144 (2008). 32. Gong, S. et al. Calibrating DFT formation enthalpy calculations by multiﬁdelity machine learning. JACS Au 2, 1964–1977 (2022). 33. Lu, T., Li, H., Li, M., Wang, S. & Lu, W. Inverse design of hybrid organic–inorganic perovskites with suitable bandgaps via proactive searching progress. ACS omega 7, 21583–21594 (2022). 34. Breiman, L. Random forests. Mach. Learn. 45, 5–32 (2021). 35. Svetnik,V. et al. Randomforest: a classiﬁcation and regression tool for compound classiﬁcation and QSAR modeling. J. Chem. Inf. Comput. Sci. 43, 1947–1958 (2003). 36. Loh, W. Y. Classiﬁcation and regression trees. Wiley Interdiscip. Rev. 1, 14–23 (2011). 37. Cutler, A., Cutler, D. R. & Stevens, J. R. Random Forests. In Ensemble Machine Learning (ed. Zhang, C. & Ma, Y.) 157-175 (Springer, 2012). 38. Loh, W. Y. Fifty years of classiﬁcation and regression trees. Int. Stat. Rev. 82, 329–348 (2014). 39. Lundberg, S. M. et al. From local explanations to global understanding with explainable AI for trees. Nat. Mach. Intell. 2, 56–67 (2020). 40. Osei-Agyemang, E. & Balasubramanian, G. Surface oxidation mechanism of a refractory high-entropy alloy. npj Mater. Degrad 3, 20 (2019). 41. Searson, P., Nagarkar, P. & Laianision, R. The effect of density of states, work function and exchange integral of polycrystalline and single crystal surfaces on the hydrogen evolution reaction. Int. J. Hydrog. Energy 14, 131–136 (1989). 42. Kadowaki, M. et al. First-principles analysis of the inhibitive effect of interstitial carbon on an active dissolution of martensitic steel. Corros. Sci. 163, 108251 (2020). 43. Chen, S. et al. Chemical-afﬁnity disparity and exclusivity drive atomic segregation, short-range ordering, and cluster formation in high- entropy alloys. Acta Mater. 206, 116638 (2021). 44. Chen, X. et al. Direct observation of chemical short-range order in a medium-entropy alloy. Nature 592, 712–716 (2021). 45. Walsh, F., Zhang, M., Ritchie, R. O., Minor, A. M. & Asta, M. Extra electron reﬂections in concentrated alloys do not necessitate short- range order. Nat. Mater. 22, 926–929 (2021). 46. Byggmästar, J., Nordlund, K. & Djurabekova, F. Modeling refractory high-entropy alloys with efﬁcient machine-learned interatomic potentials: Defects and segregation. Phys. Rev. B 104, 104101 (2021). 47. Saroukhani, S. & Warner, D. H. Investigating dislocation motion through a ﬁeld of solutes with atomistic simulations and reaction rate theory. Acta Mater. 128, 77–86 (2017). 48. Ding, Q. et al. Ritchie, Real-time nanoscale observation of deformation mechanisms in CrCoNi-based medium- to high-entropy alloys at cryogenic temperatures. Mater. Today 25, 21–27 (2019). 49. Tong, Y. et al. Severe local lattice distortion in Zr-and/or Hf-containing refractorymulti-principalelementalloys.ActaMater.183,172–181(2020). 50. Fantin, A. et al. Short-range chemical order and local lattice distortion in a compositionally complex alloy. Acta Mater. 193, 329–337 (2020). 51. Liu, X. & Curtin, W. A. Atomistic simulations reveal strength reductions due to short-range order in alloys. Acta Mater. 263, 119471 (2024). 52. Hastings, W. K. Monte Carlo sampling methods using Markov chains and their applications. Biometrika 57, 97–109 (1970). 53. Kohn, W. & Sham, L. J. Self-consistent equations including exchange and correlation effects. Phys. Rev. 140, A1133 (1965). 54. Kresse, G. & Hafner, J. Ab initio molecular dynamics for open-shell transition metals. Phys. Rev. B 48, 13115 (1993). 55. Kresse, G. & Furthmüller, J. Efﬁcient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169 (1996). 56. Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953 (1994). 57. Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865 (1996). 58. Monkhorst, H. J. & Pack, J. D. Special points for Brillouin-zone integrations. Phys. Rev. B 13, 5188 (1976). 59. Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758 (1999). 60. Cowley, J. M. X-ray measurement of order in single crystals of Cu3Au. J. Appl. Phys. 21, 24–30 (1950). Acknowledgements This research was funded by the Guangdong Province Key Area R&D Program (Grant nos. 2019B030302011 and 2019B010940001), the National Natural Science Foundation of China (Grant no. 52371050), and the China National Nuclear. Corporation (Grant no. WDZC-2023-AW-0303). Author contributions XinpengZhao:Conceptualization,Datacuration,Investigation,Writing-original draft, Writing-review & editing; Haiyou Huang: Conceptualization, Data cura- tion, Investigation, Methodology, Supervision, Validation, Funding acquisition, Writing-review & editing; Yanjing Su: Data curation, Writing-review; Lijie Qiao: Conceptualization, Investigation, Writing-review & editing; Yu Yan: Super- vision, Project administration, Funding acquisition, Writing-review & editing. Competing Interests The authors declare no competing interests. Additional information Correspondence and requests for materials should be addressed to Haiyou Huang or Yu Yan. Reprints and permissions information is available at http://www.nature.com/reprints Publisher’s note Springer Nature remains neutral withregardtojurisdictional claims in published maps and institutional afﬁliations. https://doi.org/10.1038/s41529-024-00495-1 Article npj Materials Degradation |   (2024) 8:77  10 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2024 https://doi.org/10.1038/s41529-024-00495-1 Article npj Materials Degradation |   (2024) 8:77  11
Title: Exploring high corrosion-resistant refractory high-entropy alloy via a combined experimental and simulation study
Authors: Xinpeng Zhao, Haiyou Huang, Yanjing Su, Lijie Qiao, Yu Yan
Publisher: Published in partnership with CSCP and USTB ​
Date: 2024-07-07 00:00:00
Abstract: Refractory high-entropy alloys (HEAs) have attracted considerable attention due to their stable phase structure and excellent high-temperature properties. ​ In this work, we performed first-principles calculations, coupled with experiments, to explore HEAs with high corrosion resistance. ​ The results revealed that TiNbTa-based HEAs exhibited a lower tendency for corrosion. ​ However, the appearance of local chemical fluctuations (LCFs) increased the corrosion tendency of TiNbTa-based HEAs. ​ Comprehensive SHapley Additive exPlanations analyses uncovered that in a sample with configurational LCFs, the atomic order near the surface was altered. ​ Therefore, corrosion behavior was affected. ​ Based on experiments, the annealed samples exhibited typical chemical segregation and declined corrosion resistance.