Interfacial reactions between sapphire and Ag-Cu-Ti-based active braze alloys
Interfacial reactions between sapphire and Ag-Cu-Ti-based active braze alloys
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DOI：
10.1016/j.actamat.2015.11.019
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发表时间：
2016-01
期刊：
影响因子：
9.4
通讯作者：
Majed Ali;K. Knowles;P. Mallinson;J. Fernie
中科院分区：
文献类型：
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作者：
Majed Ali;K. Knowles;P. Mallinson;J. Fernie
研究了两种市售Ag-Cu-Ti基活性钎料与蓝宝石的界面反应。在单独的实验中，Ag-35.3Cu-1.8Ti wt.%和Ag-26.7Cu-4.5Ti wt.%合金夹在R-平面取向的蓝宝石片之间，并在氩气中加热至750 - 900 °C的温度1分钟。用选区电子衍射、能量色散X射线谱和电子能量损失谱研究了Ag-Cu-Ti/蓝宝石界面的物相，观察到Ag-Cu-Ti/蓝宝石界面随温度的变化逐渐发生细微的变化，沿着形成一个允许蓝宝石润湿的过渡相。明确的证据表明，当活跃的钎焊合金熔化，钛首先迁移到蓝宝石和反应溶解高达1033原子%。氧，形成化学组成为Ti 2 O 1-x（x ≤ 1）的纳米尺寸的多晶层。Ti 3Cu 3 O颗粒随后在Ti 2 O 1-x层后面成核并生长成为连续的微米级层，取代Ti 2 O 1-x层。最后，在845 °C下，在蓝宝石上形成纳米尺寸的γ-TiO层，从而留下Ag-Cu/Ti 3Cu 3 O/γ-TiO/蓝宝石的典型界面结构，这与在用这些活性钎焊合金连接到其自身的多晶氧化铝样品中所见的界面结构一致。这些实验观察已被用来建立一个明确的连接机制，蓝宝石与银铜合金激活少量的钛。
The 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–xlayer and grow to become a continuous micrometre-size layer, replacing the Ti2O1–xlayer. 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.