Refractory high entropy alloys (HEA) are promising materials for high temperature applications. This work presents investigations of the room temperature tensile mechanical properties of selected 3 and 4 elements medium entropy alloys (MEA) derived from the HfNbTaTiZr system. Tensile testing was combined with fractographic and microstructure analysis, using scanning electron microscope (SEM), wavelength dispersive spectroscope (WDS) and X-Ray powder diffraction (XRD). The 5 element HEA alloy HfNbTaTiZr exhibits the best combination of strength and elongation while 4 and 3 element MEAs have lower strength. Some of them are ductile, some of them brittle, depending on microstructure. Simultaneous presence of Ta and Zr in the alloy resulted in a significant reduction of ductility caused by reduction of the BCC phase content. Precipitation of Ta rich particles on grain boundaries reduces further the maximum elongation to failure down to zero values.

Department of Materials Engineering Institute of Plasma Physics CAS Za Slovankou 1782 1820 Praha 8 Czech Republic

Faculty of Mathematics and Physics Charles University 5 Holešovičkách 2 18000 Praha 8 Czech Republic

UJP PRAHA a s Nad Kamínkou 1345 156 10 Praha 5 Zbraslav Czech Republic

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Miracle D.B., Senkov O.N. A critical review of high entropy alloys and related concepts. Acta Mater. 2016;122:448–511. doi: 10.1016/j.actamat.2016.08.081. DOI

Zhang W., Liaw P.K., Zhang Y. Science and technology in high-entropy alloys. Science China Materials, January. 2018;61:2–22. doi: 10.1007/s40843-017-9195-8. DOI

Cantor B., Chang IT H., Knight P., Vincent AJ B. Microstructural development in equiatomic multicomponent alloys. Mater. Sci. Eng. A. 2004;377:213–218. doi: 10.1016/j.msea.2003.10.257. DOI

Yeh B.J., Chen S., Lin S., Gan J., Chin T., Shun T., Tsau C. Nanostructured High-Entropy Alloys with Multiple Principal Elements: Novel Alloy Design Concepts and Outcomes. Adv. Eng. Mater. 2004;6:299–303. doi: 10.1002/adem.200300567. DOI

Schön C.G., Duong T., Wang Y., Arróyave R. Probing the entropy hypothesis in highly concentrated alloys. Acta Mater. 2018;148:263–279. doi: 10.1016/j.actamat.2018.01.028. DOI

Otto F., Yang Y., Bei H., George E.P. Relative effects of enthalpy and entropy on the phase stability of equiatomic high-entropy alloys. Acta Mater. 2018;61:2628–2638. doi: 10.1016/j.actamat.2013.01.042. DOI

Li Z., Ludwig A., Savan A., Springer H., Raabe D. Combinatorial metallurgical synthesis and processing of high-entropy alloys. J. Mater. Res. 2018;33:3156–3169. doi: 10.1557/jmr.2018.214. DOI

Tsai M., Yeh J., Tsai M., Yeh J. High-Entropy Alloys: A Critical Review High-Entropy Alloys: A Critical Review. Mater. Res. Lett. 2014;2:107–123. doi: 10.1080/21663831.2014.912690. DOI

Rost C.M., Sachet E., Borman T., Moballegh A., Dickey E.C., Hou D., Jones J.L., Curtarolo S., Maria J.P. Entropy-stabilized oxides. Nat. Commun. 2015;6:1–8. doi: 10.1038/ncomms9485. PubMed DOI PMC

Senkov O.N., Miracle D.B., Chaput K.J. Development and exploration of refractory high entropy alloys—A review. J. Mater. Res. 2018;33:3092–3128. doi: 10.1557/jmr.2018.153. DOI

Niinomi M., Nakai M., Hieda J. Development of new metallic alloys for biomedical applications. Acta Biomater. 2012;8:3888–3903. doi: 10.1016/j.actbio.2012.06.037. PubMed DOI

Niinomi M. Recent Research and Development in Titanium Alloys for Biomedical Applications and Healthcare Goods Recent research and development in titanium alloys for biomedical applications and healthcare goods. Sci. Technol. Adv. Mater. 2003;4:445–454. doi: 10.1016/j.stam.2003.09.002. DOI

Wang S., Xu J. TiZrNbTaMo high-entropy alloy designed for orthopedic implants: As-cast microstructure and mechanical properties. Mater. Sci. Eng. C. 2017;73:80–89. doi: 10.1016/j.msec.2016.12.057. PubMed DOI

Todai M., Nagase T., Hori T., Matsugaki A., Sekita A., Nakano T. Scripta Materialia Novel TiNbTaZrMo high-entropy alloys for metallic biomaterials. SMM. 2017;129:65–68. doi: 10.1016/j.scriptamat.2016.10.028. DOI

Li H.F., Xie X.H., Zhao K., Wang Y.B., Zheng Y.F., Wang W.H., Qin L. In vitro and in vivo studies on biodegradable CaMgZnSrYb high-entropy bulk metallic glass. Acta Biomater. 2013;9:8561–8573. doi: 10.1016/j.actbio.2013.01.029. PubMed DOI

Nnamchi P.S. First principles studies on structural, elastic and electronic properties of new Ti-Mo-Nb-Zr alloys for biomedical applications. JMADE. 2016;108:60–67. doi: 10.1016/j.matdes.2016.06.066. DOI

Pogrebnjak A.D., Beresnev V.M., Jurga S. Structural and mechanical characterization of (TiZrNbHfTa) N/WN multilayered nitride coatings. Mater. Lett. 2018;229:364–367. doi: 10.1016/j.matlet.2018.07.048. DOI

Zyka J., Malek J., Pala Z., Andrsova I., Vesely J. Structure And Mechanical Properties Of TaNbHfZrTi High Entropy Alloy; Proceedings of the METAL 2015—24rd International Conference on Metallurgy and Materials; Brno, Czech Republic. 3–5 June 2015; pp. 3–8.

Senkov O.N., Scott J.M., Senkova S.V., Miracle D.B., Woodward C.F. Microstructure and room temperature properties of a high-entropy TaNbHfZrTi alloy. J. Alloys Compd. 2011;509:6043–6048. doi: 10.1016/j.jallcom.2011.02.171. DOI

Senkov O.N., Zhang C., Pilchak A.L., Payton E.J., Woodward C., Zhang F. CALPHAD-aided development of quaternary multi-principal element refractory alloys based on NbTiZr. J. Alloys Compd. 2019;783:729–742. doi: 10.1016/j.jallcom.2018.12.325. DOI

Senkov O.N., Rao S., Chaput K.J., Woodward C. Acta Materialia Compositional effect on microstructure and properties of NbTiZr-based complex concentrated alloys. Acta Mater. 2018;151:201–215. doi: 10.1016/j.actamat.2018.03.065. DOI

Coelho A.A. TOPAS. Coelho Software; Brisbane, Australia: 2016. Version 5; Computer Software.

Standard Test Methods for Determining Average Grain Size. ASTM; West Conshohocken, PA, USA: 2013. ASTM E112-13.

Lukac F., Dudr M., Musalek R., Klecka J., Cinert J., Cizek J., Chraska T., Cizek J., Melikhova O., Kuriplach J., et al. Introduction, Spark plasma sintering of gas atomized high-entropy alloy HfNbTaTiZr. J. Mater. Res. 2018;33:3247–3257. doi: 10.1557/jmr.2018.320. DOI

Nguyen V.T., Shi Z., Song T. Compositional design of strong and ductile (tensile) Ti-Zr-Nb-Ta medium entropy alloys (MEAs) using the atomic mismatch approach. Mater. Sci. Eng. A. 2019;742:762–772. doi: 10.1016/j.msea.2018.11.054. DOI

Maiti S., Steurer W. Structural-disorder and its effect on mechanical properties in single- phase TaNbHfZr high-entropy alloy. Acta Mater. 2016;106:87–97. doi: 10.1016/j.actamat.2016.01.018. DOI

Couzinié J.P., Dirras G., Perrière L., Chauveau T., Leroy E., Champion Y., Guillot I. Microstructure of a near-equimolar refractory high-entropy alloy. Mater. Lett. 2014;126:285–287. doi: 10.1016/j.matlet.2014.04.062. DOI

Sheikh S., Shafeie S., Hu Q., Ahlström J., Persson C., Veselý J., Zýka J. Alloy design for intrinsically ductile refractory high-entropy alloys Alloy design for intrinsically ductile refractory high-entropy alloys. J. Appl. Phys. 2016;120 doi: 10.1063/1.4966659. DOI

Takeuchi A., Inoue A. Classification of Bulk Metallic Glasses by Atomic Size Difference, Heat of Mixing and Period of Constituent Elements and Its Application to Characterization of the Main Alloying Element. Mater. Trans. 2005;46:2817–2829. doi: 10.2320/matertrans.46.2817. DOI

Okamoto H. Ta-Zr (Tantalum-Zirconium) J. Phase Equilib. 1996;17:555. doi: 10.1007/BF02666009. DOI

Okamoto H. Nb-Zr (Niobium-Zirconium) J. Phase Equilib. 1992;13:577. doi: 10.1007/BF02665776. DOI

Okamoto H. Hf-Ta (Hafnium-Tantalum) J. Phase Equilib. 1996;17:382. doi: 10.1007/BF02667626. DOI

Okamoto H. Hf-Nb (Hafnium-Niobium) J. Phase Equilib. 1998;19:288. doi: 10.1361/105497198770342490. DOI

Wu Y.D., Cai Y.H., Chen X.H., Wang T., Si J.J., Wang L., Wang Y.D., Hui X.D. Phase composition and solid solution strengthening effect in TiZrNbMoV high-entropy alloys. Mater. Des. 2015;83:651–660. doi: 10.1016/j.matdes.2015.06.072. DOI

Schuh B., Volker B., Todt J., Schell N., Perriere L., Li J., Couzinie J.P., Hohenwarter A. Thermodynamic instability of a nanocrystalline, single-phase TiZrNbHfTa alloy and its impact on the mechanical properties. Acta Mater. 2018;142:201–212. doi: 10.1016/j.actamat.2017.09.035. DOI

Coury F.G., Butler T., Chaput K., Saville A., Copley J., Foltz J., Mason P., Clarke K., Kaufman M., Clarke A. Phase equilibria, mechanical properties and design of quaternary refractory high entropy alloys. Mater. Des. 2018;155:244–256. doi: 10.1016/j.matdes.2018.06.003. DOI

Stepanov N.D., Yurchenko N.Y., Zherebtsov S.V., Tikhonovsky M.A., Salishchev G.A. Aging behavior of the HfNbTaTiZr high entropy alloy. Mater. Lett. 2018;211:87–90. doi: 10.1016/j.matlet.2017.09.094. DOI

Chen S.Y., Tong Y., Tseng K., Yeh J., Poplawsky J.D., Wen J.G., Gao M.C., Kim G., Chen W., Ren Y., et al. Phase transformations of HfNbTaTiZr high-entropy alloy at intermediate temperatures. Scr. Mater. 2019;158:50–56. doi: 10.1016/j.scriptamat.2018.08.032. DOI

Sheikh S., Bijaksana M.K., Motallebzadeh A., Shafeie S., Lozinko A., Gan L., Tsao T., Klement U., Canadinc D., Murakami H., et al. Accelerated oxidation in ductile refractory high-entropy alloys. Intermetallics. 2018;97:58–66. doi: 10.1016/j.intermet.2018.04.001. DOI

Influence of Molybdenum on the Microstructure, Mechanical Properties and Corrosion Resistance of Ti20Ta20Nb20(ZrHf)20-xMox (Where: x = 0, 5, 10, 15, 20) High Entropy Alloys