体系组织结构及元素扩散行为的影响
( 中南大学 材料科学与工程学院， 长沙 410083)
摘 要: 采用电弧离子镀(AIP)技术在Ti6Al4V基体表面沉积制备了NiCrAlY涂层。 通过金相观察(OM)、 扫描电镜(SEM)与能谱(EDS)分析、 X射线衍射(XRD)分析以及显微硬度测试， 研究了真空热处理对NiCrAlY涂层组织性能的影响， 讨论了Ti6Al4V基体/NiCrAlY涂层界面元素扩散规律。 结果表明： 700 ℃真空热处理后， NiCrAlY涂层中开始析出γ′-Ni3Al相， 这提高了涂层的表面硬度； 在700 ℃温度下， Ti6Al4V基体/NiCrAlY涂层界面由外至内出现Ni3(Al,Ti)、 TiNi和Ti2Ni中间化合物层， 并随着温度提高， 界面处中间化合物层增厚； 700 ℃时， 主要发生了镍、 钛元素的扩散， 铬元素在870 ℃开始发生扩散。 当温度提高到950 ℃后， 由于镍元素大量向Ti6Al4V基体扩散引起涂层的退化失效。
关键字: NiCrAlY涂层； 真空热处理； 显微组织； 扩散
（ School of Materials Science and Engineering,
Central South University, Changsha 410083, China）
Abstract: NiCrAlY coating was deposited on Ti6Al4V substrate by arc ion plating (AIP). OM, SEM, EDS, XRD analysis, microhardness test were used to characterize the microstructure and morphology of the NiCrAlY coating, and the influence of vacuum heat treatment on the elements diffusion behavior was studied. The results show that γ′-Ni3Al phase is precipitated in NiCrAlY coating after heat treatment, which can increase the microhardness of the coating. Ni3(Al, Ti), TiNi and Ti2Ni intermetallic layers appear at the interface from outside to inside after 700℃ heat treatment, and the thickness of intermetallic layers is increased with the increasing temperature. At 700 ℃ Ti and Ni are the major diffusion elements and the diffusion of Cr occurs when the heat treatment temperature increases up to 870 ℃.The violent inward diffusion of Ni at 950 ℃ causes the degradation of NiCrAlY coating.
Key words: NiCrAlY coating; vacuum heat treatment; microstructure; diffusion
