【摘要】 采用低温超音速火焰喷涂（LT-HVOF）在钛合金（Ti6Al4V）基体表面制备纯Al涂层后进行真空热处理,获得了厚度约300μm的TiAl₃-Al复合涂层,并对该涂层在700℃下长时间高温氧化行为进行了研究,用SEM,EDS和XRD分析了涂层的形貌、成分及相组成.结果表明:低温超音速火焰喷涂制备的纯Al涂层结构较为致密,但存在少量的微孔洞,经真空热处理后的纯Al涂层与钛合金基体间在界面处形成了TiAl₃互扩散层;再700℃下静态氧化时,随着时间的增加,涂层表面形成了一层薄而致密的Al₂O₃和TiO₂的混合氧化层,而涂层中纯Al与基体中的Ti互扩散逐渐转变为TiAl₃;氧化约5h后涂层进入稳态氧化阶段,高温氧化500h后涂层未出现剥落等现象,表明TiAl₃-Al复合涂层能显著提高Ti6Al4V合金的抗高温氧化性能.更多还原

【Abstract】 In this study,pure Al coating was prepared on titanium alloy（Ti6Al4V）by the LT-HVOF process,TiAl₃-Al composite coatings were gained by applying heat treatment at 610℃.Long-term high temperature oxidation behavior at 700℃of the coatings was investigated.The microstructure,chemical and phase composition of the coatings were investigated using SEM,EDS and XRD.The experimental results show that the pure Al coating fabricated by LT-HOVF is dense and there are some micro-holes in the coating.TiAl₃ diffusion layer between pure Al coating and titanium alloy substrate is formed after vacuum heat treatment.Isothermal oxidation test at 700℃ shows that a thin and dense Al₂O₃ and TiO₂ mixed oxides layer is formed on the surface of the coating.TiAl₃ is transformed by interdiffusion between Al coating and Ti alloy substrate.After high temperature oxidation of 5 h,coating entered steady-state oxidation stage.After 500 hhigh temperature oxidation,spallation is not observed in the coating.The high temperature oxidation resistance ability of titanium alloy（Ti6Al4V）can be significantly enhanced by TiAl₃-Al composite coatings.更多还原