(沈陽工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽 110870)
摘 要: 通過中溫蠕變性能測試、組織形貌觀察及位錯組態(tài)的衍襯分析，研究無Re鎳基單晶合金的蠕變行為與變形機制。結(jié)果表明：在760 ℃、750 MPa條件下，合金具有良好的蠕變抗力及較長的蠕變壽命，蠕變期間，合金中的γ′相僅發(fā)生粗化，未發(fā)生筏形化轉(zhuǎn)變。合金在蠕變初期的變形機制是(1/2) 位錯在基體通道的{111}八面體滑移系中運動，蠕變位錯可發(fā)生單取向滑移、雙取向滑移和交滑移；隨著蠕變進入后期，合金的應(yīng)變增大，其變形機制是 位錯在基體中運動和剪切進入γ′相，其中，基體中的位錯發(fā)生扭曲，而部分剪切進入γ′相的 超位錯發(fā)生分解，形成 肖克萊不全位錯+層錯的位錯組態(tài)，可抑制位錯的交滑移，使合金具有較好的蠕變抗力。
關(guān)鍵字: 鎳基單晶合金；蠕變性能；組織演化；位錯組態(tài)；變形機制
（School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China）
Abstract:By means of creep property measurement at intermediate temperature, microstructure observation and contrast analysis of dislocation configuration, the creep behavior and deformation mechanism of Re-free nickel-based single crystal superalloy at intermediate temperature were investigated. The results show that the alloy displays a better creep resistance and long creep life at 760 ℃, 750 MPa. During creep at intermediate temperature, the coarsening of the cubical γ′ phase occurs, and no rafting transformation of γ′ phase is detected. The deformation mechanism of the superalloy during initial creep is the slipping of (1/2) dislocations with single oriented, double oriented and cross-slipping features activated on the octahedral systems in the γ matrix channels. The strain of the alloy increases as the creep enters latter stage, the deformation mechanism of the superalloy is that dislocations slipping in the γ matrix and shearing enter into the cubical γ′ phase. Thereinto, the twisting of dislocations in the matrix occurs, and some super-dislocations shearing into γ′ phase may be decomposed to form the configuration of super-Shockleys particles and the stacking faults, which may hinder the cross-slipping of dislocations, improve the creep resistance of the superalloy and make the superalloy having the better creep resistance.
Key words: nickel-based single crystal superalloy; creep property; microstructure evolution; dislocation configuration; deformation mechanism
