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dc.contributor.authorAli, Majeden
dc.contributor.authorKnowles, Kevinen
dc.contributor.authorMallinson, Phillip Men
dc.contributor.authorFernie, John Aen
dc.date.accessioned2015-11-09T17:59:37Z
dc.date.available2015-11-09T17:59:37Z
dc.date.issued2015-12-07en
dc.identifier.citationActa Materialia 2015, 103: 859–869. doi:10.1016/j.actamat.2015.11.019en
dc.identifier.issn1359-6454
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/252568
dc.description.abstractThe interfacial reactions between two commercially available Ag–Cu–Ti-based active braze alloys and sapphire have been studied. In separate experiments, Ag– 35.3Cu–1.8Ti wt.% and Ag–26.7Cu–4.5Ti wt.% alloys have been sandwiched between pieces of R-plane orientated sapphire and heated in argon to temperatures between 750 and 900 °C for 1 min. The phases at the Ag–Cu– Ti/sapphire interfaces have been studied using selected area electron diffraction, energy dispersive X-ray spectroscopy and electron energy loss spectroscopy. Gradual and subtle changes at the Ag–Cu–Ti/sapphire interfaces were observed as a function of temperature, along with the formation of a transient phase that permitted wetting of the sapphire. Unequivocal evidence is shown that when the active braze alloys melt, titanium first migrates to the sapphire and reacts to dissolve up to ~33 at.% oxygen, forming a nanometre-size polycrystalline layer with a chemical composition of Ti₂O₁₋ₓ (x<<1). Ti₃Cu₃O particles subsequently nucleate behind the Ti₂O₁₋ₓ layer and grow to become a continuous micrometre-size layer, replacing the Ti₂O₁₋ₓ layer. Finally at 845 °C, a nanometre-size γ-TiO layer forms on the sapphire to leave a typical interfacial structure of Ag–Cu/Ti₃Cu₃O/γ-TiO/sapphire consistent with that seen in samples of polycrystalline alumina joined to itself with these active braze alloys. These experimental observations have been used to establish a definitive bonding mechanism for the joining of sapphire with Ag–Cu alloys activated by small amounts of titanium
dc.description.sponsorshipWe are grateful for the financial support for this study provided by AWE.
dc.languageEnglishen
dc.language.isoenen
dc.publisherElsevier
dc.rightsAttribution-NonCommercial-NoDerivs 2.0 UK: England & Wales*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/2.0/uk/*
dc.titleInterfacial reactions between sapphire and Ag-Cu-Ti-based active braze alloyen
dc.typeArticle
dc.description.versionThis is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.actamat.2015.11.019en
prism.endingPage869
prism.publicationDate2015en
prism.publicationNameActa Materialiaen
prism.startingPage859
prism.volume103en
rioxxterms.versionofrecord10.1016/j.actamat.2015.11.019en
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2015-12-07en
dc.identifier.eissn1873-2453
rioxxterms.typeJournal Article/Reviewen
rioxxterms.freetoread.startdate2016-12-07


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Attribution-NonCommercial-NoDerivs 2.0 UK: England & Wales
Except where otherwise noted, this item's licence is described as Attribution-NonCommercial-NoDerivs 2.0 UK: England & Wales