(1. 沈陽工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽 110870；
2. 北京航空材料研究院，北京 100095)
摘 要: 通過蠕變曲線測(cè)定及組織形貌觀察，研究[001]、[011]取向鎳基單晶合金在蠕變期間的組織演化及變形特征。結(jié)果表明：經(jīng)完全熱處理后，[001]和[011]取向合金中立方γ′相均以共格方式鑲嵌在γ基體相中，并沿 取向規(guī)則排列。蠕變期間，[001]取向合金中γ′相沿垂直于應(yīng)力軸方向形成N-型筏狀組織，而[011]取向合金中γ′相沿[001]取向形成纖維狀筏形組織，且在(100)晶面的筏狀γ′相與施加應(yīng)力軸方向呈45°角排列，其中，立方γ′相不同晶面中擴(kuò)張晶格的法線方向是筏狀γ′相的生長(zhǎng)方向。在試驗(yàn)溫度和應(yīng)力范圍內(nèi)，與[011]取向合金相比，[001]取向合金具有較好的蠕變抗力。在高溫蠕變后期，兩取向合金中的筏狀γ′相均發(fā)生粗化和扭折，其中，[001]取向合金在蠕變后期的變形機(jī)制是位錯(cuò)剪切γ′相，而[011]取向合金的變形特征主要是形變位錯(cuò)在基體通道中滑移。
關(guān)鍵字: 單晶鎳基合金；晶體取向；蠕變；組織演化；變形特征
single crystal nickel-based superalloy
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China;
2. Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract:By means of the measurement of creep curves and microstructure observation, the microstructure evolution and creep behaviors of [001] and [011] oriented single crystal nickel-base superalloy during tensile creep were investigated. The results show that, after fully heat treated, the microstructure of [001] and [011] oriented single crystal nickel-base superalloy consists of the cubical γ′ phase embedded coherent in the γ matrix and arranged regularly along the orientations. During creep, the cubical γ′ phase in [001] orientation alloy is transformed into the N-type rafted structure along the direction vertical to the applied stress axis. However, the cubical γ′ phase in [011] orientation superalloy is transformed into the strip-like rafted structure along [001] orientation during creep, and the orientation of the rafted γ′ phase is 45° relative to the direction of the applied stress axis on (100) crystal plane. Thereinto, the normal of the expanding lattice on the different crystal planes of the cubical γ′ phase is thought to be the growth direction of the rafted phase. In the ranges of the applied stresses and temperatures, compared to [011] orientation alloy, [001] orientation alloy has a better creep resistance and a longer creep life. In the later period of high temperature creep, the rafted γ′ phase in [001] and [011] orientations alloy is gradually coarsened and twisted. The dislocations shearing the rafted γ′ phase and slipping within the γ matrix channels are thought to be the deformation mechanisms of [001] and [011] orientations alloys, respectively.
Key words: single crystal nickel-base superalloy; crystal orientation; creep; microstructure evolution; deformation features
