{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:38:09Z","timestamp":1760143089043,"version":"build-2065373602"},"reference-count":31,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2024,1,24]],"date-time":"2024-01-24T00:00:00Z","timestamp":1706054400000},"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>The processing and characterizing of bonding Ti6Al4V to Al2O3 brazed joints using interlayer thin films was investigated. The brazing was conducted in a tubular furnace with an argon flux at 980 \u00b0C for 30 min. The brazing fillers consisted of different combinations of thin Ag\/Cu and Ti films with variable thicknesses. The joint interface analysis involved using digital microscopy (DM) and optical microscopy (OM). Microstructural characterization and chemical composition were performed via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Mechanical properties were assessed through microhardness and shear strength tests. Brazing successfully produced interfaces with a combination of titanium films and Ag\/Cu as brazing filler. The results revealed that the interface mainly comprises Ti2Cu, TiCu2Al, \u03b1-Ti, and Ti2(Cu,Ag). Some segregation of (Ag) was observed at the interfaces, but a decrease in its amount was observed when compared to joints produced using Ag\/Cu fillers. The thickness of the titanium film in the brazing filler strongly influenced the integrity of the joints. The amount of (Ag) at the interface diminished as the Ti film\u2019s thickness decreased, leading to an improvement in the mechanical properties of the joints. Using a combination of Ag\/Cu and Ti thin films revealed a potential approach to reduce the segregation of soft phases at interfaces, promoting a significant improvement in joining metal to ceramic materials.<\/jats:p>","DOI":"10.3390\/met14020146","type":"journal-article","created":{"date-parts":[[2024,1,24]],"date-time":"2024-01-24T09:57:42Z","timestamp":1706090262000},"page":"146","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Microstructure and Mechanical Properties of Ti6Al4V to Al2O3 Brazed Joints Using Ti-Ag\/Cu-Ti Thin Films"],"prefix":"10.3390","volume":"14","author":[{"given":"Beatriz","family":"Monteiro","sequence":"first","affiliation":[{"name":"Department of Metallurgical and Materials Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4670-4516","authenticated-orcid":false,"given":"S\u00f3nia","family":"Sim\u00f5es","sequence":"additional","affiliation":[{"name":"Department of Metallurgical and Materials Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"LAETA\/INEGI, Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,1,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"6570","DOI":"10.1016\/j.matpr.2021.04.047","article-title":"Recent advances and development in joining ceramics to metals","volume":"46","author":"Mir","year":"2021","journal-title":"Mater. Today Proc."},{"unstructured":"Peters, M., Hemptenmacher, J., Kumpfert, J., Leyens, C., Terlinde, G., and Fischer, G. (2003). Titanium and Titanium Alloys, Wiley-VCH.","key":"ref_2"},{"doi-asserted-by":"crossref","unstructured":"Joshi, V.A. (2006). Titanium Alloys, CRC Press.","key":"ref_3","DOI":"10.1201\/9781420006063"},{"doi-asserted-by":"crossref","unstructured":"Appel, F., Paul, J.D.H., and Oehring, M. (2011). Gamma Titanium Aluminide Alloys: Science and Technology, Wiley-VCH.","key":"ref_4","DOI":"10.1002\/9783527636204"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1046","DOI":"10.2355\/isijinternational.30.1046","article-title":"Recent advances in joining technology of ceramics to metals","volume":"30","author":"Suganuma","year":"1990","journal-title":"ISIJ Int."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1011","DOI":"10.2355\/isijinternational.30.1011","article-title":"Metal\/ceramic joining","volume":"30","author":"Elssner","year":"1990","journal-title":"ISIJ Int."},{"key":"ref_7","first-page":"C7-1317","article-title":"Ceramic\/metal joining for structures and materials","volume":"3","author":"Tomsia","year":"1993","journal-title":"J. Phys. IV"},{"doi-asserted-by":"crossref","unstructured":"Sharon Uwanyuze, R., Yavas, B., Zhang, J., Kanyo, J.E., Frame, L.D., Hebert, R.J., Schaffoner, S., and Pamir Alpay, S. (2023). High-temperature interactions between titanium alloys and strontium zirconate refractories. J. Mater. Eng. Perform.","key":"ref_8","DOI":"10.1007\/s11665-023-08597-8"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1263","DOI":"10.1016\/j.matchar.2009.05.007","article-title":"Al2O3\/Ti6Al4V diffusion bonding joints using Ag\u2013Cu interlayer","volume":"60","author":"Barrena","year":"2009","journal-title":"Mater. Charact."},{"doi-asserted-by":"crossref","unstructured":"Silva, M., Ramos, A.S., and Sim\u00f5es, S. (2021). Joining Ti6Al4V to alumina by diffusion bonding using titanium interlayers. Metals, 11.","key":"ref_10","DOI":"10.3390\/met11111728"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"592","DOI":"10.1016\/j.matdes.2014.01.029","article-title":"Evaluation on diffusion bonded joints of TiAl alloy to Ti3SiC2 ceramic with and without Ni interlayer: Interfacial microstructure and mechanical properties","volume":"57","author":"Liu","year":"2014","journal-title":"Mater. Des."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"111665","DOI":"10.1016\/j.matchar.2021.111665","article-title":"Diffusion bonding of implantable Al2O3\/Ti-13Nb-13Zr joints: Interfacial microstructure and mechanical properties","volume":"184","author":"Bian","year":"2022","journal-title":"Mater. Charact."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"110216","DOI":"10.1016\/j.vacuum.2021.110216","article-title":"Improvement of microstructure and mechanical properties of dissimilar friction stir welded aluminum\/titanium joints via aluminum oxide nanopowder","volume":"188","author":"Shehabeldeen","year":"2021","journal-title":"Vacuum"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"110430","DOI":"10.1016\/j.vacuum.2021.110430","article-title":"Microstructure and mechanical properties of Al2O3 ceramic and Ti2AlNb alloy joints brazed with Al2O3 particles reinforced Ag\u2013Cu filler metal","volume":"192","author":"Peng","year":"2021","journal-title":"Vacuum"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1942","DOI":"10.1016\/j.jmrt.2021.02.048","article-title":"Microstructure, characterization of interfacial phases and mechanical properties of high Nb\u2013TiAl\/Al2O3 joints brazed by novel Nb particle-reinforced Ag\u2013Cu filler alloy","volume":"11","author":"Dong","year":"2021","journal-title":"J. Mater. Res. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"118272","DOI":"10.1016\/j.jmatprotec.2023.118272","article-title":"Profiling interfacial reaction features and mechanical properties of B4C ceramic and Ti6Al4V titanium alloy brazed with Ag-based brazing filler","volume":"324","author":"Chen","year":"2024","journal-title":"J. Mater. Process. Technol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"617","DOI":"10.1016\/j.jeurceramsoc.2007.06.017","article-title":"Joining of partially sintered alumina to alumina, titanium, Hastealloy and C\u2013SiC composite using Ag\u2013Cu brazes","volume":"28","author":"Asthana","year":"2008","journal-title":"J. Eur. Ceram. Soc."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1252","DOI":"10.1016\/j.actamat.2009.10.029","article-title":"Brazing copper to alumina using reactive CuAgTi alloys","volume":"58","author":"Kozlova","year":"2010","journal-title":"Acta Mater."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1016\/j.msea.2007.12.049","article-title":"Bond strength and microstructure investigation of Al2O3\/Al\/Al2O3 joints with surface modification of alumina by titanium","volume":"495","author":"Ksiazek","year":"2008","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"555","DOI":"10.1016\/j.matchar.2006.12.001","article-title":"Characterization of interface of Al2O3\u2013304 stainless steel braze joint","volume":"58","author":"Kar","year":"2007","journal-title":"Mater. Charact."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1016\/j.msea.2011.12.042","article-title":"Processing, microstructure and mechanical properties of vacuum-brazed Al2O3\/Ti6Al4V joints","volume":"535","author":"Cao","year":"2012","journal-title":"Mater. Sci. Eng. A"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"513","DOI":"10.1007\/s40194-022-01448-5","article-title":"Microstructure, mechanical properties and corrosion behaviour of Ti6Al4V\/Al2O3 joints brazed with TiCuNi filler","volume":"67","author":"Alves","year":"2023","journal-title":"Weld. World"},{"doi-asserted-by":"crossref","unstructured":"Emadinia, O., Guedes, A., Tavares, C.J., and Sim\u00f5es, S. (2020). Joining Alumina to Titanium Alloys Using Ag\u2013Cu Sputter-Coated Ti Brazing Filler. Materials, 13.","key":"ref_23","DOI":"10.3390\/ma13214802"},{"key":"ref_24","first-page":"156","article-title":"Al\u2013Cu\u2013Ti (Aluminum\u2013Copper\u2013Titanium)","volume":"27","author":"Raghavan","year":"2006","journal-title":"J. Phase Equilibria Diffus."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"286","DOI":"10.3139\/146.110472","article-title":"Thermodynamic modelling of the Ag\u2013Cu\u2013Ti ternary system","volume":"102","author":"Dezellus","year":"2011","journal-title":"Int. J. Mater. Res."},{"doi-asserted-by":"crossref","unstructured":"Fergus, J.W. (2010). High Temperature Corrosion of Intermetallic Alloys, Elsevier. Shreir\u2019s Corrosion.","key":"ref_26","DOI":"10.1016\/B978-044452787-5.00078-0"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4015","DOI":"10.1007\/s11661-012-1226-1","article-title":"Phase Equilibria of the Cu-Ti-Er System at 773 K (500 \u00b0C) and Stability of the CuTi3 Phase","volume":"43","author":"Zhan","year":"2012","journal-title":"Metall. Mater. Trans. A Phys."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"6924","DOI":"10.1016\/j.ceramint.2016.01.078","article-title":"Microstructure and mechanical properties of Al2O3 ceramic and TiAl alloy joints brazed with Ag\u2013Cu\u2013Ti filler metal","volume":"42","author":"Niu","year":"2016","journal-title":"Ceram. Int."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/j.vacuum.2018.01.019","article-title":"Microstructure and mechanical properties of transparent alumina and TiAl alloy joints brazed using Ag\u2013Cu\u2013Ti filler metal","volume":"151","author":"Liu","year":"2018","journal-title":"Vacuum"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"3177","DOI":"10.1007\/s11661-004-0062-3","article-title":"Infrared brazing Cu and Ti using a 95Ag-5Al braze alloy","volume":"35","author":"Shiue","year":"2004","journal-title":"Metall. Mater. Trans. A Phys."},{"unstructured":"Villars, P., and Prince, A. (1995). Okamoto Handbook of Ternary Alloy Phase Diagrams, ASM International.","key":"ref_31"}],"container-title":["Metals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4701\/14\/2\/146\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T13:48:40Z","timestamp":1760104120000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4701\/14\/2\/146"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,1,24]]},"references-count":31,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2024,2]]}},"alternative-id":["met14020146"],"URL":"https:\/\/doi.org\/10.3390\/met14020146","relation":{},"ISSN":["2075-4701"],"issn-type":[{"type":"electronic","value":"2075-4701"}],"subject":[],"published":{"date-parts":[[2024,1,24]]}}}