(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 機(jī)械學(xué)院，畢節(jié) 551700)
摘 要: 通過(guò)對(duì)6%Re/5%Ru單晶鎳基合金(質(zhì)量分?jǐn)?shù))進(jìn)行蠕變性能測(cè)試和組織觀察，研究了合金的超高溫蠕變行為和影響因素。結(jié)果表明：測(cè)定出合金在(1160 ℃，120 MPa)的蠕變壽命為206 h。中期穩(wěn)態(tài)階段，位錯(cuò)在基體中滑移和攀移越過(guò)γ′相是合金的變形特征，γ基體中溶解的難熔元素可增加位錯(cuò)在基體中運(yùn)動(dòng)的阻力。超高溫蠕變期間，隨溫度提高γ′相發(fā)生溶解，可減小筏狀γ′相的尺寸，提高位錯(cuò)攀移越過(guò)γ′相的速率，特別是當(dāng)溫度大于1170 ℃時(shí)，合金的施加溫度敏感性使筏狀γ′相的尺寸減小，應(yīng)變速率提高，這是合金蠕變壽命大幅度降低的主要原因。蠕變后期，基體位錯(cuò)可在位錯(cuò)網(wǎng)破損處切入γ′相，其中，切入γ′相的位錯(cuò)可由{111}面交滑移至{100}面形成K-W鎖，抑制位錯(cuò)的滑移和交滑移，可改善合金的蠕變抗力。而在頸縮區(qū)域較大的有效應(yīng)力可開(kāi)動(dòng)位錯(cuò)的雙取向滑移，致使筏狀γ′相扭折，并在扭折區(qū)域發(fā)生裂紋的萌生和擴(kuò)展，直至斷裂，這是合金在超高溫蠕變期間的變形和損傷機(jī)制。
關(guān)鍵字: 單晶鎳基合金；6.0%Re/5.0%Ru；超高溫蠕變；位錯(cuò)網(wǎng)；變形；損傷；K-W鎖
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China;
2. School of Mechanical Engineering, Guizhou University of Engineering Science, Bijie 551700, China）
Abstract:Through the creep properties test and microstructure observation of a 6%Re/5%Ru single crystal nickel-based superalloy, the ultra-high temperature creep behavior and influencing factors of the alloy were studied. The results show that the creep life of the alloy at (1160 ℃, 120 MPa) is 206 h. The deformation features of alloy in the middle creep period is large number of dislocations sliding in γ matrix and climbing over γ′ phase, the refractory elements dissolving in γ matrix may increase the resistance of dislocation movement. During creep at ultra-high temperature, the γ′ phase dissolves as the temperature increases, which can reduce the size of the rafted γ′ phase and increase the rate of dislocations climbing over the rafted γ′ phase. Especially, when the temperature is higher than 1170 ℃, the applied temperature sensitivity of the alloy diminishes the size of the rafted γ′ phase and increases the strain rate, which is the main reason for drastically reducing creep life of the alloy. In the later creep period, the dislocations can shear into γ′ phase from the damaging region of dislocation networks. The K-W locks can be formed by the cross-slip of dislocations from the {111} plane to the {100} plane, which can inhibit the slip and cross-slip of dislocations. The larger effective stress in the necking area can activate the double orientations sliding of dislocations, causing the rafted γ′ phase to twist, and crack initiation and propagation in the contorted regions until fracture, which is the mechanism of the deforming and damaging features of alloy during creep at ultra-high temperature.
Key words: single crystal nickel-based superalloy; 6%Re/5%Ru; ultra-high temperature creep; dislocation networks; deformation; damage; K-W locks
