Ti-6Al-4V(Ti64) alloy has excellent mechanical properties and corrosion resistances, but poor oxidation properties at high temperatures. It is necessary to improve the oxidation resistances of the alloy in order to expand its application in the aerospace and automotive fields. This study aimed to improve oxidation resistances through diffusion coatings on the surface of the alloy. Aluminide coatings on Ti64 alloys have been investigated via pack aluminium process at temperature ranges of 400–800 °C. Al and/or TiAl₃ layers were formed at the interface between the Ti64 alloy and the Al coating layer, when the Ti64 alloys were heat-treated at 400 and 500 °C. TiAl₃ layer was manufactured on Ti64 alloys at 600, 700 and 800 °C. The growth of the coated TiAl₃ layer followed diffusional growth manner, and the estimated value of the nucleation barrier was the lowest among the intermediate phases of the Ti-Al system. The coating kinetics were discussed together with free energy diagram observations. The activation energy for growth of the TiAl₃ layer was estimated as ~82 kJ/mol in the experimental temperature ranges. At the same time, isothermal oxidation tests of the bare Ti64 alloy and the aluminized Ti64 alloys were performed at 1000 °C. By confirming the diffusion pathway of the Ti-Al-O ternary system, the oxidation behaviours and resistances of the alloys were compared and analysed.

Ti-6Al-4V(Ti64)合金具有优良的机械性能和耐腐蚀性能，但高温氧化性能较差。为了扩大其在航空航天和汽车领域的应用，必须提高合金的抗氧化性。本研究旨在通过合金表面的扩散涂层来提高抗氧化性。在 400–800 °C 的温度范围内，通过包铝工艺研究了 Ti64 合金上的铝化物涂层。当 Ti64 合金在 400 和 500 °C 下进行热处理时，在 Ti64 合金和 Al 涂层之间的界面处形成了Al 和/或 TiAl ₃层。TiAl ₃层是在 Ti64 合金上在 600、700 和 800 °C 下制造的。涂层 TiAl ₃的生长层，随后扩散的生长方式，和估计值的核势垒的是钛铝系统的中间阶段中最低的。涂层动力学用自由能图的观察一起进行讨论。为TiAl金属的生长激活能₃层被估计为〜82千焦/摩尔在实验温度范围。同时，裸Ti64合金和镀铝Ti64合金的等温氧化测试在1000进行℃。通过确认在Ti-Al系-O三元体系的扩散路径，氧化行为和合金的电阻进行比较分析。