| To predict the nearest-alumina reaction product between alumina and titanium (for solid pure Ti and liquid Cu-l0at%Ti alloy) thermodynamic calculation was carried out, and its result was compared with experimental observations. Joining experiments were performed using Ti-containing alloy (Cu-Ag-Ti), 99.9% titanium sheet and titanium coat at 1193-1393 K for 1.2-3.6 ks by vacuum brazing (〈10^(-5)Torr) and diffusion bonding (〈10^(-4)Torr). At 1193 K, the Al-Ti-O ternary phase diagram for reaction products between alumina and solid titanium was proposed. With the temperature and oxygen mole fraction, the Cu-Al-Ti-O quaternary phase diagram was proposed for reaction products between alumina and liquid Cu-l0at%Ti alloy. The redox reaction product is varied with the application method of titanium, i.e. from TiO [nonstoichiometric TiO_(1±x(x=0.1))] to TiAl and Ti₃Al. That is because the behavior of aluminium and oxygen decomposed form alumina by titanium is varied with the application method (according to whether solid or liquid) and a volume of titanium. These experimental results were well agreed with the thermodynamic prediction. |
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