(1. 沈陽(yáng)工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽(yáng) 110870； 2. 貴州工程應(yīng)用技術(shù)學(xué)院，畢節(jié) 551700)
摘 要: 通過(guò)對(duì)有/無(wú)Ru單晶鎳基合金進(jìn)行時(shí)效處理、蠕變性能測(cè)試及組織形貌觀察，研究元素Ru對(duì)鎳基單晶合金組織結(jié)構(gòu)與蠕變行為的影響。結(jié)果表明：加入Ru使合金中元素Co由負(fù)偏析轉(zhuǎn)為正偏析，熱處理可大幅度降低元素在枝晶干/間的偏析程度。無(wú)Ru單晶鎳基合金在1080 ℃時(shí)效期間沿{111}晶面析出富含難熔元素的針狀μ相，而無(wú)Ru合金加入2%Ru(質(zhì)量分?jǐn)?shù))后，可抑制合金中析出TCP相。與無(wú)Ru合金相比，2%Ru合金在980 ℃、200 MPa的蠕變壽命由123 h提高到333 h。合金在蠕變后期的變形機(jī)制是位錯(cuò)在基體中滑移和剪切筏狀γ′相，其中，主、次滑移位錯(cuò)的交替開(kāi)動(dòng)，使其筏狀γ′相轉(zhuǎn)變成不規(guī)則的扭曲形態(tài)。與2%Ru合金相比，無(wú)Ru合金中析出大量的針狀μ相，可促使裂紋的萌生和擴(kuò)展，直到蠕變斷裂，是使無(wú)Ru合金具有較低蠕變抗力和較短蠕變壽命的主要原因。
關(guān)鍵字: 單晶鎳基合金；元素Ru；顯微組織；TCP相；蠕變；變形特征
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China; 2. Guizhou University of Engineering Science, Bijie 551700, China）
Abstract:By means of aged treatment, creep property measurement and microstructure observation, the influence of element Ru on the microstructure and creep behavior of single crystal nickel-based superalloy was investigated. The results show that the Co is a negative segregation element in Ru-free alloy, whereas adding Ru makes Co transform into positive segregation element. And the segregation extent of elements on the dendrite/inter-dendrite regions may be decreased, to a great extent, by heat treatment. During being aged at 1080 ℃, the slice-like μ phase is precipitated along {111} plane in Ru-free superalloy, and the precipitation of TCP phase may be restrained by adding 2%Ru (mass fraction). Compared to Ru-free alloy, the creep life of the 2%Ru superalloy at 980 ℃, 200 MPa increases form 123 h to 333 h. The deformation mechanism of alloy in the later stage of creep is dislocations slipping in γ matrix and shearing into the rafted g? phase, wherein, the alternate activation of the primary/secondary slipping dislocations results in the twisted of the rafted g? phase to form the irregular configuration. Compared to 2%Ru alloy, the slice-like μ phase precipitated in Ru-free alloy may promote the initiation and propagation of cracks up to fracture, which is thought to be the main reason of the alloy having a lower creep resistances and shorter lifetime.
Key words: single crystal nickel-based superalloy; element Ru; microstructure; TCP phase; creep; deformation feature
