體系組織結(jié)構(gòu)及元素?cái)U(kuò)散行為的影響
( 中南大學(xué) 材料科學(xué)與工程學(xué)院， 長(zhǎng)沙 410083)
摘 要: 采用電弧離子鍍(AIP)技術(shù)在Ti6Al4V基體表面沉積制備了NiCrAlY涂層。 通過金相觀察(OM)、 掃描電鏡(SEM)與能譜(EDS)分析、 X射線衍射(XRD)分析以及顯微硬度測(cè)試， 研究了真空熱處理對(duì)NiCrAlY涂層組織性能的影響， 討論了Ti6Al4V基體/NiCrAlY涂層界面元素?cái)U(kuò)散規(guī)律。 結(jié)果表明： 700 ℃真空熱處理后， NiCrAlY涂層中開始析出γ′-Ni3Al相， 這提高了涂層的表面硬度； 在700 ℃溫度下， Ti6Al4V基體/NiCrAlY涂層界面由外至內(nèi)出現(xiàn)Ni3(Al,Ti)、 TiNi和Ti2Ni中間化合物層， 并隨著溫度提高， 界面處中間化合物層增厚； 700 ℃時(shí)， 主要發(fā)生了鎳、 鈦元素的擴(kuò)散， 鉻元素在870 ℃開始發(fā)生擴(kuò)散。 當(dāng)溫度提高到950 ℃后， 由于鎳元素大量向Ti6Al4V基體擴(kuò)散引起涂層的退化失效。
關(guān)鍵字: NiCrAlY涂層； 真空熱處理； 顯微組織； 擴(kuò)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
