{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T11:00:27Z","timestamp":1777374027500,"version":"3.51.4"},"reference-count":43,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2018,12,25]],"date-time":"2018-12-25T00:00:00Z","timestamp":1545696000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["107-3017-F-007-003"],"award-info":[{"award-number":["107-3017-F-007-003"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>Nowadays refractory high-entropy alloys (RHEAs) are regarded as great candidates for the replacement of superalloys at high temperature. To design a RHEA, one must understand the pros and cons of every refractory element. However, the elemental effect on mechanical properties remains unclear. In this study, the subtraction method was applied on equiatomic HfMoNbTaTiZr alloys to discover the role of each element, and, thus, HfMoNbTaTiZr, HfNbTaTiZr, HfMoTaTiZr, HfMoNbTiZr, HfMoNbTaZr, and HfMoNbTaTi were fabricated and analyzed. The microstructure and mechanical properties of each alloy at the as-cast state were examined. The solid solution phase formation rule and the solution strengthening effect are also discussed. Finally, the mechanism of how Mo, Nb, Ta, Ti, and Zr affect the HfMoNbTaTiZr alloys was established after comparing the properties of these alloys.<\/jats:p>","DOI":"10.3390\/e21010015","type":"journal-article","created":{"date-parts":[[2018,12,26]],"date-time":"2018-12-26T04:29:54Z","timestamp":1545798594000},"page":"15","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":128,"title":["Effects of Mo, Nb, Ta, Ti, and Zr on Mechanical Properties of Equiatomic Hf-Mo-Nb-Ta-Ti-Zr Alloys"],"prefix":"10.3390","volume":"21","author":[{"given":"Ko-Kai","family":"Tseng","sequence":"first","affiliation":[{"name":"Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan"}]},{"given":"Chien-Chang","family":"Juan","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan"}]},{"given":"Shuen","family":"Tso","sequence":"additional","affiliation":[{"name":"High Entropy Materials Center, National Tsing Hua University, Hsinchu 30013, Taiwan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7694-4900","authenticated-orcid":false,"given":"Hsuan-Chu","family":"Chen","sequence":"additional","affiliation":[{"name":"High Entropy Materials Center, National Tsing Hua University, Hsinchu 30013, Taiwan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3072-7916","authenticated-orcid":false,"given":"Che-Wei","family":"Tsai","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan"},{"name":"High Entropy Materials Center, National Tsing Hua University, Hsinchu 30013, Taiwan"}]},{"given":"Jien-Wei","family":"Yeh","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan"},{"name":"High Entropy Materials Center, National Tsing Hua University, Hsinchu 30013, Taiwan"}]}],"member":"1968","published-online":{"date-parts":[[2018,12,25]]},"reference":[{"key":"ref_1","unstructured":"International, A.S.M., and Handbook, C. (1990). Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM International. [10th ed.]. ASM Handbook."},{"key":"ref_2","unstructured":"Smith, W.F. (1993). Structure and Properties of Engineering Alloys, McGraw-Hill. [2nd ed.]."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Reed, R.C. (2006). The Superalloys: Fundamentals and Applications, Cambridge University Press.","DOI":"10.1017\/CBO9780511541285"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Kawagishi, K., Yeh, A.C., Yokokawa, T., Kobayashi, T., Koizumi, Y., and Harada, H. (2012). Development of an Oxidation-Resistant High-Strength Sixth-Generation Single-Crystal Superalloy TMS-238. Superalloys.","DOI":"10.7449\/2012\/Superalloys_2012_189_195"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Prasad, N.E., and Wanhill, R.J.H. (2017). Niobium and Other High Temperature Refractory Metals for Aerospace Applications. Aerospace Materials and Material Technologies: Volume 1: Aerospace Materials, Springer.","DOI":"10.1007\/978-981-10-2143-5"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1002\/adem.200300567","article-title":"Nanostructured high-entropy alloys with multiple principal elements: Novel alloy design concepts and outcomes","volume":"6","author":"Yeh","year":"2004","journal-title":"Adv. Eng. Mater."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"633","DOI":"10.3166\/acsm.31.633-648","article-title":"Recent progress in high-entropy alloys","volume":"31","author":"Yeh","year":"2006","journal-title":"Annales de Chimie Science des Mat\u00e9riaux"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"448","DOI":"10.1016\/j.actamat.2016.08.081","article-title":"A critical review of high entropy alloys and related concepts","volume":"122","author":"Miracle","year":"2017","journal-title":"Acta Mater."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1016\/j.cossms.2017.09.002","article-title":"Physical metallurgy of concentrated solid solutions from low-entropy to high-entropy alloys","volume":"21","author":"Cheng","year":"2017","journal-title":"Curr. Opin. Solid State Mater."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1759","DOI":"10.1007\/s11837-013-0761-6","article-title":"Alloy Design Strategies and Future Trends in High-Entropy Alloys","volume":"65","author":"Yeh","year":"2013","journal-title":"JOM"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Gao, M.C., Yeh, J.W., Liaw, P.K., and Zhang, Y. (2016). High-Entropy Alloys: Fundamentals and Applications, Springer International Publishing. [1st ed.].","DOI":"10.1007\/978-3-319-27013-5"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Murty, B.S., Yeh, J.W., and Ranganathan, S. (2014). High Entropy Alloys, Butterworth-Heinemann.","DOI":"10.1016\/B978-0-12-800251-3.00002-X"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"4887","DOI":"10.1016\/j.actamat.2013.04.058","article-title":"Sluggish diffusion in Co\u2013Cr\u2013Fe\u2013Mn\u2013Ni high-entropy alloys","volume":"61","author":"Tsai","year":"2013","journal-title":"Acta Mater."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"C531","DOI":"10.1149\/2.028311jes","article-title":"Superior Oxidation Resistance of (Al0.34Cr0.22Nb0.11Si0.11Ti0.22)50N50 High-Entropy Nitride","volume":"160","author":"Shen","year":"2013","journal-title":"J. Electrochem. Soc."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Shi, Y., Yang, B., and Liaw, P. (2017). Corrosion-Resistant High-Entropy Alloys: A Review. Metals, 7.","DOI":"10.3390\/met7020043"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1007\/s11431-017-9137-4","article-title":"Fatigue behavior of high-entropy alloys: A review","volume":"61","author":"Chen","year":"2017","journal-title":"Sci. China Technol. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"12658","DOI":"10.1038\/s41598-017-13026-7","article-title":"The High Temperature Tensile and Creep Behaviors of High Entropy Superalloy","volume":"7","author":"Tsao","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1153","DOI":"10.1126\/science.1254581","article-title":"A fracture-resistant high-entropy alloy for cryogenic applications","volume":"345","author":"Gludovatz","year":"2014","journal-title":"Science"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Senkov, O.N., Miracle, D.B., Chaput, K.J., and Couzinie, J.-P. (2018). Development and exploration of refractory high entropy alloys\u2014A review. J. Mater. Res., 1\u201337.","DOI":"10.1557\/jmr.2018.153"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Yeh, A.C., Tsao, T.K., Chang, Y.J., Chang, K.C., Yeh, J.W., Chiou, M.S., Jian, S.R., Kuo, C.M., Wang, W.R., and Murakami, H. (2015). Developing New Type of High Temperature Alloys\u2013High Entropy Superalloys. Int. J.Metall. Mater. Eng., 1.","DOI":"10.15344\/2455-2372\/2015\/107"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"6200","DOI":"10.1038\/srep06200","article-title":"A promising new class of high-temperature alloys: Eutectic high-entropy alloys","volume":"4","author":"Lu","year":"2014","journal-title":"Sci. Rep."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Kumar, A., and Gupta, M. (2016). An Insight into Evolution of Light Weight High Entropy Alloys: A Review. Metals, 6.","DOI":"10.3390\/met6090199"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1758","DOI":"10.1016\/j.intermet.2010.05.014","article-title":"Refractory high-entropy alloys","volume":"18","author":"Senkov","year":"2010","journal-title":"Intermetallics"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"698","DOI":"10.1016\/j.intermet.2011.01.004","article-title":"Mechanical properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 refractory high entropy alloys","volume":"19","author":"Senkov","year":"2011","journal-title":"Intermetallics"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"6043","DOI":"10.1016\/j.jallcom.2011.02.171","article-title":"Microstructure and room temperature properties of a high-entropy TaNbHfZrTi alloy","volume":"509","author":"Senkov","year":"2011","journal-title":"J. Alloys Compd."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"4062","DOI":"10.1007\/s10853-012-6260-2","article-title":"Microstructure and elevated temperature properties of a refractory TaNbHfZrTi alloy","volume":"47","author":"Senkov","year":"2012","journal-title":"J. Mater. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Yurchenko, N., Stepanov, N., Tikhonovsky, M., and Salishchev, G. (2016). Phase Evolution of the AlxNbTiVZr (x = 0; 0.5; 1; 1.5) High Entropy Alloys. Metals, 6.","DOI":"10.3390\/met6120298"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1016\/j.jallcom.2014.11.064","article-title":"Effect of Al addition on mechanical properties and microstructure of refractory AlxHfNbTaTiZr alloys","volume":"624","author":"Lin","year":"2015","journal-title":"J. Alloys Compd."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"284","DOI":"10.1016\/j.matlet.2016.03.133","article-title":"Solution strengthening of ductile refractory HfMoxNbTaTiZr high-entropy alloys","volume":"175","author":"Juan","year":"2016","journal-title":"Mater. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Waseem, O.A., Lee, J., Lee, H.M., and Ryu, H.J. (2017). The effect of Ti on the sintering and mechanical properties of refractory high-entropy alloy TixWTaVCr fabricated via spark plasma sintering for fusion plasma-facing materials. Mater. Chem. Phys.","DOI":"10.1016\/j.matchemphys.2017.06.054"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"651","DOI":"10.1016\/j.matdes.2015.06.072","article-title":"Phase composition and solid solution strengthening effect in TiZrNbMoV high-entropy alloys","volume":"83","author":"Wu","year":"2015","journal-title":"Mater. Des."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1016\/j.msea.2017.08.019","article-title":"Structure and mechanical properties of B2 ordered refractory AlNbTiVZrx (x = 0\u20131.5) high-entropy alloys","volume":"704","author":"Yurchenko","year":"2017","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"534","DOI":"10.1002\/adem.200700240","article-title":"Solid-Solution Phase Formation Rules for Multi-Component Alloys","volume":"10","author":"Zhang","year":"2008","journal-title":"Adv. Eng. Mater."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.matchemphys.2011.11.021","article-title":"Prediction of high-entropy stabilized solid-solution in multi-component alloys","volume":"132","author":"Yang","year":"2012","journal-title":"Mater. Chem. Phys."},{"key":"ref_35","unstructured":"Boer, F.R.d. (1988). Cohesion in Metals: Transition Metal Alloys, North-Holland."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2817","DOI":"10.2320\/matertrans.46.2817","article-title":"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","volume":"46","author":"Takeuchi","year":"2005","journal-title":"Mater. Trans."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"103505","DOI":"10.1063\/1.3587228","article-title":"Effect of valence electron concentration on stability of fcc or bcc phase in high entropy alloys","volume":"109","author":"Guo","year":"2011","journal-title":"J. Appl. Phys."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1016\/j.actamat.2014.04.033","article-title":"Electronic and thermodynamic criteria for the occurrence of high entropy alloys in metallic systems","volume":"75","author":"Poletti","year":"2014","journal-title":"Acta Mater."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1016\/S1002-0071(12)60080-X","article-title":"Phase stability in high entropy alloys: Formation of solid-solution phase or amorphous phase","volume":"21","author":"Guo","year":"2011","journal-title":"Prog. Nat. Sci: Mater. Int."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"5132","DOI":"10.1021\/ja9928677","article-title":"Configuration Energies of the d-Block Elements","volume":"122","author":"Mann","year":"2000","journal-title":"J. Am. Chem. Soc."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1080\/02670836.2016.1153277","article-title":"Laves-phase formation criterion for high-entropy alloys","volume":"33","author":"Yurchenko","year":"2016","journal-title":"Mater. Sci. Technol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1139","DOI":"10.1016\/j.jallcom.2016.11.188","article-title":"Mechanical properties of refractory high-entropy alloys: Experiments and modeling","volume":"696","author":"Yao","year":"2017","journal-title":"J. Alloy. Compd."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1016\/j.matlet.2016.08.060","article-title":"Simultaneously increasing the strength and ductility of a refractory high-entropy alloy via grain refining","volume":"184","author":"Juan","year":"2016","journal-title":"Mater. Lett."}],"container-title":["Entropy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1099-4300\/21\/1\/15\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:36:00Z","timestamp":1760196960000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1099-4300\/21\/1\/15"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,12,25]]},"references-count":43,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2019,1]]}},"alternative-id":["e21010015"],"URL":"https:\/\/doi.org\/10.3390\/e21010015","relation":{},"ISSN":["1099-4300"],"issn-type":[{"value":"1099-4300","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,12,25]]}}}