(1. 中國(guó)礦業(yè)大學(xué)(北京) 機(jī)電與信息工程學(xué)院，北京 100083；
2. 貴州工程應(yīng)用技術(shù)學(xué)院 機(jī)械工程學(xué)院，畢節(jié) 551700)
摘 要: 通過(guò)蠕變性能測(cè)試和組織觀察，研究4.5%Re/3%Ru鎳基單晶合金在高溫的蠕變行為和損傷特征。結(jié)果表明：測(cè)定出該合金在(1100 ℃, 140 MPa)下的蠕變壽命為476 h。合金在高溫穩(wěn)態(tài)蠕變期間的變形機(jī)制是位錯(cuò)在γ基體中滑移和攀移越過(guò)筏形γ′相，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，剪切進(jìn)入γ′相的位錯(cuò)可由{111}面交滑移至{100}面，形成的K-W鎖+APB組態(tài)，可改善合金的抗蠕變性能。隨著大量 位錯(cuò)的交替滑移使筏狀γ/γ′兩相扭曲、折斷及筏狀γ′相的晶體旋轉(zhuǎn)，使其成為亞晶結(jié)構(gòu)，可降低合金的蠕變抗力。兩滑移系的交替開動(dòng)可使筏狀γ/γ′兩相界面出現(xiàn)微裂紋，并沿與應(yīng)力軸垂直方向發(fā)生裂紋的擴(kuò)展，直至蠕變斷裂，是合金在高溫蠕變后期的損傷與斷裂機(jī)制。
關(guān)鍵字: 鎳基單晶合金；Re/Ru；組織結(jié)構(gòu)；蠕變損傷；變形機(jī)制
（1. School of Mechanical Electronic & Information Engineering, China University of Mining & Technology, Beijing 100083, China;
2. School of Mechanical Engineering, Guizhou University of Engineering Science, Bijie 551700, China）
Abstract:The creep behavior and damage feature of a 4.5%Re/3%Ru-containing single crystal nickel-based superalloy at high temperature were investigated of creep property measurement and microstructure observation. The results show that the creep life of alloy at (1100 ℃, 140 MPa) is measured as 476 h. During steady state creep at high temperature, the deformation mechanism of alloy is dislocation slipping in γ matrix and climbing over the rafted γ′ phase. In the later stage of creep, the deformation mechanism of alloy is dislocations slipping in γ matrix and shearing into the rafted γ′ phase. Wherein the dislocations shearing into γ′ phase can cross-slip from {111} to {100} planes to form the configuration of K-W locking + APB, which may improve the creep resistance of alloy. The alternated slipping of a large number of dislocations causes both the twisting and breaking of the rafted γ/γ′ phases and the crystal rotation of γ′ phase to form the sub-grain structure, which may reduce the creep resistance of alloy. Furthermore, the alternated activation of the initiation/secondary slipping systems may promote the initiation of cracks occurring in the rafted γ/γ′ interface, and the cracks are propagated along the interface perpendicular to the stress axis until creep fracture, which is the damage and fracture mechanism of alloy in the later stage creep at high temperature.
Key words: single crystal nickel-based superalloy; Re/Ru; microstructure; creep damage; deformation mechanism
