{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,22]],"date-time":"2026-01-22T22:30:43Z","timestamp":1769121043034,"version":"3.49.0"},"reference-count":24,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2018,9,14]],"date-time":"2018-09-14T00:00:00Z","timestamp":1536883200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Metals"],"abstract":"<jats:p>Joining \u03b3-TiAl alloy to Ni-based superalloy Hastelloy using Ag-Cu sputtered coated Ti foil as brazing filler was investigated in this study. Brazing experiments were performed at 900, 950, and 980 \u00b0C with a dwelling stage of 10 min in vacuum. The microstructure and the chemical composition of the resulting interfaces were analyzed by scanning electron microscopy (SEM) and by energy dispersive X-ray spectroscopy (EDS), respectively. Sound joints were produced after brazing at 980 \u00b0C, presenting a multilayered interface, consisting mainly of Ti-Al and Ti-Ni-Al intermetallics close to the \u03b3-TiAl alloy, and of Ti-rich, Ti-Ni, and Cr-Ni-Mo rich phases near Hastelloy. The hardness of the interface, ranging from around 300 to 1100 HV0.01, is higher than both base materials, but no segregation of either Ag solid solution or coarse intermetallic particles was observed. Therefore, the developed brazing filler also avoids the need to perform post-brazing heat treatments that aim to eliminate detrimental extensive segregation of either soft phases or of hard and brittle compounds.<\/jats:p>","DOI":"10.3390\/met8090723","type":"journal-article","created":{"date-parts":[[2018,9,14]],"date-time":"2018-09-14T10:57:59Z","timestamp":1536922679000},"page":"723","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Joining of \u03b3-TiAl Alloy to Ni-Based Superalloy Using Ag-Cu Sputtered Coated Ti Brazing Filler Foil"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4670-4516","authenticated-orcid":false,"given":"S\u00f3nia","family":"Sim\u00f5es","sequence":"first","affiliation":[{"name":"CEMMPRE, Department of Metallurgical and Materials Engineering, University of Porto, R. Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"INEGI-Institute of Science and Innovation in Mechanical and Industrial Engineering, R. Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5757-0096","authenticated-orcid":false,"given":"Carlos Jos\u00e9","family":"Tavares","sequence":"additional","affiliation":[{"name":"Centre of Physics, Minho University, Azur\u00e9m, 4800-058 Guimar\u00e3es, Portugal"}]},{"given":"An\u00edbal","family":"Guedes","sequence":"additional","affiliation":[{"name":"CMEMS-UMinho, Department of Mechanical Engineering, Minho University, Azur\u00e9m, 4800-058 Guimar\u00e3es, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2018,9,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1016\/S0921-5093(98)01158-7","article-title":"Gamma titanium aluminide alloys-an assessment within the competition of aerospace structural materials","volume":"263","author":"Dimiduk","year":"1999","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Leyens, C., and Peters, M. (2003). Titanium and Titanium Alloys: Fundamentals and Applications, WILEY-VCH Verlag GmbH & Co. KGaA.","DOI":"10.1002\/3527602119"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1557\/opl.2013.44","article-title":"The science, technology and implementation of TiAl alloys in commercial aircraft engines","volume":"1516","author":"Bewlay","year":"2013","journal-title":"MRS Symp. Proc."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"784","DOI":"10.1016\/j.jallcom.2016.06.212","article-title":"High temperature oxidation behavior and research status of modifications on improving high temperature oxidation resistance of titanium alloys and titanium aluminides: A review","volume":"685","author":"Dai","year":"2016","journal-title":"J. Alloys Compd."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1080\/09603409.2016.1183068","article-title":"TiAl alloys in commercial aircraft engines","volume":"33","author":"Bewlay","year":"2016","journal-title":"Mater. High Temp."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Tomashchuk, I., and Sallamand, P. (2018). Metallurgical strategies for the joining of titanium alloys with steels. Adv. Eng. Mater., 20.","DOI":"10.1002\/adem.201700764"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1017\/S1431927614013087","article-title":"TEM and HRTEM characterization of TiAl diffusion bonds using Ni\/Al nanolayers","volume":"21","author":"Viana","year":"2015","journal-title":"Microsc. Microanal."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Sim\u00f5es, S., Ramos, A.S., Viana, F., Vieira, M.T., and Vieira, M.F. (2016). Joining of TiAl to steel by diffusion bonding with Ni\/Ti reactive multilayers. Metals, 6.","DOI":"10.3390\/met6050096"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"4930","DOI":"10.3390\/ma7074930","article-title":"Welding and joining of titanium aluminides","volume":"7","author":"Cao","year":"2014","journal-title":"Materials"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2409","DOI":"10.1023\/A:1023948917115","article-title":"Joining Ti-47Al-2Cr-2Nb with a Ti\/(Cu,Ni)\/Ti clad-laminated braze alloy","volume":"38","author":"Guedes","year":"2003","journal-title":"J. Mater. Sci."},{"key":"ref_11","first-page":"225","article-title":"Diffusion vacuum brazing of TiAl47 casting alloy based on TiAl (\u03b3) intermetallic compound using Ag-Cu-Ti braze alloy","volume":"52","author":"Rozanski","year":"2014","journal-title":"Kov. Mater."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1016\/j.matdes.2018.02.020","article-title":"An analysis of high-temperature microstructural stability and mechanical performance of the Hastelloy N-Hastelloy N Superalloy joint bonded with pure Ti","volume":"144","author":"He","year":"2018","journal-title":"Mater. Des."},{"key":"ref_13","unstructured":"Hardesty, R., Jensen, M., and Grant, L. (1989). High Temperature Be Panel Development, NASA. NASA Contract Report 181777."},{"key":"ref_14","unstructured":"Guedes, A., Mollaoglu, H., Viana, F., Pinto, A.M.P., and Vieira, M.F. (2010, January 11\u201317). Brazing Ti-47Al-2Cr-2Nb to Inconel 718 with different filler alloys: Microstructural characterization of the interfaces. Proceedings of the International Conference on Advances in Welding Science and Technology for Construction, Energy and Transportation, Istanbul, Turkey."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Xu, Q., Chaturvedi, M.C., Richards, N.L., and Goel, N. (1997, January 21). Diffusion brazing of a Ti-45Al-2Nb-2Mn+0.8vol.%TiB~2 XD alloy. Proceedings of the Second International Symposium, Structural Intermetallics, Champion, PA, USA.","DOI":"10.1016\/S0921-5093(97)00637-0"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1333","DOI":"10.4028\/www.scientific.net\/MSF.514-516.1333","article-title":"Assessing the influence of heat treatments on -TiAl joints","volume":"514\u2013516","author":"Guedes","year":"2006","journal-title":"Mater. Sci. Forum"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Wang, Y., Xia, Y.H., Yang, Z.W., and Wang, D.P. (2018). Interfacial microstructure and mechanical properties of TC4\/Ti3SiC2 contact-reactive brazed joints using a Cu interlayer. Ceram. Int.","DOI":"10.1016\/j.ceramint.2018.08.328"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Sim\u00f5es, S., Soares, A., Tavares, C.J., and Guedes, A. (2018). Joining of TiAl alloy using novel Ag-Cu sputtered coated Ti brazing filler. Microsc. Microanal., under review.","DOI":"10.3390\/met8090723"},{"key":"ref_19","unstructured":"Mitra, R. (2018). 4-Titanium aluminides. Intermetallic Matrix Composites, Woodhead Publishing."},{"key":"ref_20","unstructured":"Villars, P., Prince, A., and Okamoto, H. (1995). Handbook of Ternary Alloy Phase Diagrams, ASM International."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/j.calphad.2013.02.004","article-title":"Thermodynamics of Ti-Ni shape memory alloys","volume":"41","author":"Cirstea","year":"2013","journal-title":"Calphad"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"522","DOI":"10.1016\/j.msea.2015.03.108","article-title":"Brazing high Nb containing TiAl alloy using Ti\u201328Ni eutectic brazing alloy: Interfacial microstructure and joining properties","volume":"636","author":"Si","year":"2015","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"929","DOI":"10.1016\/j.intermet.2004.02.006","article-title":"Infrared brazing of TiAl intermetallic using pure silver","volume":"12","author":"Shiue","year":"2004","journal-title":"Intermetallics"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1023\/A:1014269923133","article-title":"Vacuum brazing TiAl-based alloy to 40Cr steel using Ag-Cu-Zn filler metal","volume":"21","author":"Liu","year":"2002","journal-title":"J. Mater. Sci. Lett."}],"container-title":["Metals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4701\/8\/9\/723\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:20:29Z","timestamp":1760196029000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4701\/8\/9\/723"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,9,14]]},"references-count":24,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2018,9]]}},"alternative-id":["met8090723"],"URL":"https:\/\/doi.org\/10.3390\/met8090723","relation":{},"ISSN":["2075-4701"],"issn-type":[{"value":"2075-4701","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,9,14]]}}}