{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,30]],"date-time":"2026-10-30T12:03:54Z","timestamp":1793361834496,"version":"4.5.0"},"reference-count":33,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,23]],"date-time":"2026-08-23T00:00:00Z","timestamp":1787443200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Stabilization Support Research Project of CSSRC","award":["WDZC70202030101"],"award-info":[{"award-number":["WDZC70202030101"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Ti-6Al-4V titanium alloy is extensively employed in deep-sea structural applications owing to its excellent corrosion resistance, while its extra-low-interstitial (ELI) variant provides higher fracture toughness and is commonly presumed to exhibit even better stress corrosion cracking (SCC) resistance. In this work, displacement-rate-dependent fracture toughness (KQ) measurements and failure analysis were performed for compact tension specimens machined from an engineering Ti-6Al-4V ELI plate with different orientations, tested in air and 3.5 wt.% NaCl solution over displacement rates of 0.0012\u20131.2 mm\/min. In air, KQ exhibits a pronounced loading-rate dependence, decreasing by more than 20% at low displacement rates relative to maximum rate, accompanied by quasi-cleavage features on the fracture surfaces indicative of hydrogen-assisted damage, likely arising from environmental or processing-related hydrogen uptake. In 3.5 wt.% NaCl solution, the minimum KQ within the low-rate regime (0.0012\u20130.12 mm\/min) is 58 MPa\u00b7m0.5, comparable to values reported for conventional Ti-6Al-4V under similar conditions. The pronounced rate dependence and transition toward cleavage-like fracture reveal a strong coupling between loading kinetics and environmental degradation. This work demonstrates that enhanced intrinsic toughness does not necessarily translate into superior SCC resistance and establishes loading rate as a critical factor governing the environmental fracture of Ti-6Al-4V ELI under marine conditions.<\/jats:p>","DOI":"10.3390\/ma19173572","type":"journal-article","created":{"date-parts":[[2026,8,24]],"date-time":"2026-08-24T10:07:53Z","timestamp":1787566073000},"page":"3572","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Stress Corrosion Cracking of Ti-6Al-4V ELI Titanium Alloy in 3.5 wt.% NaCl Solution"],"prefix":"10.3390","volume":"19","author":[{"given":"Qing","family":"Zhao","sequence":"first","affiliation":[{"name":"China Ship Scientific Research Center, Wuxi 214082, China"},{"name":"Taihu Laboratory of Deepsea Technological Science, Wuxi 214082, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aifeng","family":"Zhang","sequence":"additional","affiliation":[{"name":"China Ship Scientific Research Center, Wuxi 214082, China"},{"name":"Taihu Laboratory of Deepsea Technological Science, Wuxi 214082, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhengquan","family":"Wan","sequence":"additional","affiliation":[{"name":"China Ship Scientific Research Center, Wuxi 214082, China"},{"name":"Taihu Laboratory of Deepsea Technological Science, Wuxi 214082, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0535-767X","authenticated-orcid":false,"given":"Yafei","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8284-0297","authenticated-orcid":false,"given":"Chengqi","family":"Sun","sequence":"additional","affiliation":[{"name":"Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Engineering Science, University of Chinese Academy of Sciences; Beijing 100049, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,23]]},"reference":[{"key":"ref_1","first-page":"133","article-title":"Properties and applications of titanium alloys: A brief review","volume":"32","author":"Veiga","year":"2012","journal-title":"Rev. Adv. Mater. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1016\/S0921-5107(97)00043-3","article-title":"Structure and composition of passive titanium oxide films","volume":"47","author":"Pouilleau","year":"1997","journal-title":"Mater. Sci. Eng. B"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"8962","DOI":"10.1016\/j.electacta.2011.07.129","article-title":"Characterization of passive films formed on titanium during anodic oxidation","volume":"56","author":"Simka","year":"2011","journal-title":"Electrochim. Acta"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Blackburn, M., Feeney, J., and Beck, T. (1973). Stress-corrosion cracking of titanium alloys. Advances in Corrosion Science and Technology, Springer.","DOI":"10.1007\/978-1-4615-8258-8_2"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"109497","DOI":"10.1016\/j.corsci.2021.109497","article-title":"AgCl-induced hot salt stress corrosion cracking in a titanium alloy","volume":"187","author":"Shi","year":"2021","journal-title":"Corros. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1199","DOI":"10.1149\/1.2131649","article-title":"Electrochemical behavior of titanium and some titanium alloys under tensile stress in boiling sulfuric acid and acidic chloride solutions","volume":"125","author":"Sinigaglia","year":"1978","journal-title":"J. Electrochem. Soc."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Ogden, H., and Jaffee, R. (1955). The Effects of Carbon, Oxygen, and Nitrogen on the Mechanical Properties of Titanium and Titanium Alloys.","DOI":"10.2172\/4370612"},{"key":"ref_8","unstructured":"Barella, S., Mapelli, C., and Venturini, R. (2005). Investigation about the stress corrosion cracking of Ti-6Al-4V. Metall. Sci. Tecnol., 23."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1007\/s10008-023-05681-w","article-title":"A poly(methyl methacrylate)\u2013ibuprofen composite film as anticorrosive coating of Ti\u20136Al\u20134 V surface","volume":"28","author":"Cotolan","year":"2024","journal-title":"J. Solid State Electrochem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"112175","DOI":"10.1016\/j.engfracmech.2026.112175","article-title":"Fatigue properties and influential factors of Ti-6Al-4V ELI titanium alloy used in deep-sea pressure hull structure","volume":"341","author":"Zhang","year":"2026","journal-title":"Eng. Fract. Mech."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"151","DOI":"10.5006\/0010-9312-24.6.151","article-title":"Stress corrosion cracking of alpha titanium alloys at room temperature","volume":"24","author":"Powell","year":"1968","journal-title":"Corrosion"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"821","DOI":"10.1016\/0010-938X(93)90102-M","article-title":"The stress corrosion cracking and hydrogen embrittlement of titanium in methanol-hydrochloric acid solutions","volume":"34","author":"Hollis","year":"1993","journal-title":"Corros. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1016\/0022-5096(89)90002-1","article-title":"Numerical analysis of hydrogen transport near a blunting crack tip","volume":"37","author":"Sofronis","year":"1989","journal-title":"J. Mech. Phys. Solids"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"6860","DOI":"10.1038\/s41467-022-34628-4","article-title":"Switching nanoprecipitates to resist hydrogen embrittlement in high-strength aluminum alloys","volume":"13","author":"Wang","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"112471","DOI":"10.1016\/j.corsci.2024.112471","article-title":"Advancing the hydrogen tolerance of ultrastrong aluminum alloys via nanoprecipitate modification","volume":"240","author":"Wang","year":"2024","journal-title":"Corros. Sci."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"14923","DOI":"10.1016\/j.ijhydene.2023.01.040","article-title":"Combined impact of elastic stress, prestrain and electrochemical charging on the hydrogen-induced cracking of high-strength steel","volume":"48","author":"Hu","year":"2023","journal-title":"Int. J. Hydrogen Energy"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"686","DOI":"10.1016\/j.actamat.2020.02.029","article-title":"Hydrogenation-induced lattice expansion and its effects on hydrogen diffusion and damage in Ti\u20136Al\u20134V","volume":"188","author":"Kim","year":"2020","journal-title":"Acta Mater."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"117304","DOI":"10.1016\/j.actamat.2021.117304","article-title":"Roughening improves hydrogen embrittlement resistance of Ti-6Al-4V","volume":"220","author":"Kim","year":"2021","journal-title":"Acta Mater."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"116383","DOI":"10.1016\/j.scriptamat.2024.116383","article-title":"Role of retrogression and reaging in suppressing hydrogen-induced transgranular cracking in 7xxx Al alloys","volume":"255","author":"Wang","year":"2025","journal-title":"Scr. Mater."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1601","DOI":"10.1016\/j.actamat.2010.11.024","article-title":"On the formation and nature of quasi-cleavage fracture surfaces in hydrogen embrittled steels","volume":"59","author":"Martin","year":"2011","journal-title":"Acta Mater."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1085","DOI":"10.1007\/s11663-015-0325-y","article-title":"Hydrogen Embrittlement Understood","volume":"46","author":"Robertson","year":"2015","journal-title":"Metall. Mater. Trans. B"},{"key":"ref_22","unstructured":"Wang, Y., Liu, Q., Shao, Y., Zhao, Q., Su, H., Wang, J., Lin, Y., Liu, Z., and Sun, C. (Corros. Sci., 2026). Mechanisms of sustained load cracking in high vacuum environment and stress corrosion cracking for Ti-6Al-4V ELI alloy in deep-sea structures, Corros. Sci., submitted."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"115804","DOI":"10.1016\/j.scriptamat.2023.115804","article-title":"Stress corrosion cracking induced by the combination of external and internal hydrogen in Al-Zn-Mg-Cu alloy","volume":"239","author":"Tang","year":"2024","journal-title":"Scr. Mater."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1520\/STP33421S","article-title":"Stress-Corrosion Cracking in Titanium Alloys","volume":"733","author":"Meyn","year":"1981","journal-title":"Fractography Mater. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1079","DOI":"10.1016\/S0142-1123(03)00145-2","article-title":"A review of dwell sensitive fatigue in titanium alloys: The role of microstructure, texture and operating conditions","volume":"25","author":"Bache","year":"2003","journal-title":"Int. J. Fatigue"},{"key":"ref_26","unstructured":"Moreira, L.C.M. (2024). Hydrogen Embrittlement of Titanium Alloys: Impact of Hydrogen on the Mechanical Behavior Under Low Cycle Fatigue. [Ph.D. Thesis, Universit\u00e9 de La Rochelle]."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1016\/0022-5096(95)00075-5","article-title":"Modeling of hydrogen transport and elastically accommodated hydride formation near a crack tip","volume":"44","author":"Lufrano","year":"1996","journal-title":"J. Mech. Phys. Solids"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2969","DOI":"10.1016\/j.actamat.2011.01.037","article-title":"Hydrogen-enhanced local plasticity at dilute bulk H concentrations: The role of H\u2013H interactions and the formation of local hydrides","volume":"59","author":"Lymperakis","year":"2011","journal-title":"Acta Mater."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"103740","DOI":"10.1016\/j.jmps.2019.103740","article-title":"Hydrogen induced fast-fracture","volume":"134","author":"Shishvan","year":"2020","journal-title":"J. Mech. Phys. Solids"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Suresh, S. (1998). Fatigue of Materials, Cambridge University Press.","DOI":"10.1017\/CBO9780511806575"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"107331","DOI":"10.1016\/j.ijfatigue.2022.107331","article-title":"Nanograin formation and cracking mechanism in Ti alloys under very high cycle fatigue loading","volume":"167","author":"Sun","year":"2023","journal-title":"Int. J. Fatigue"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"522","DOI":"10.5006\/1.3585142","article-title":"Numerical simulation of crevice corrosion of stainless steels and nickel alloys in chloride solutions","volume":"46","author":"Watson","year":"1990","journal-title":"Corrosion"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1179\/095066004225010550","article-title":"Hydrogen as a temporary alloying element in titanium alloys: Thermohydrogen processing","volume":"49","author":"Froes","year":"2004","journal-title":"Int. Mater. Rev."}],"container-title":["Materials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1944\/19\/17\/3572\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T08:04:28Z","timestamp":1787645068000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1944\/19\/17\/3572"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,23]]},"references-count":33,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["ma19173572"],"URL":"https:\/\/doi.org\/10.3390\/ma19173572","relation":{},"ISSN":["1996-1944"],"issn-type":[{"value":"1996-1944","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,23]]}}}