(沈阳工业大学 材料科学与工程学院，沈阳 110870)
摘 要: 通过中温蠕变性能测试、组织形貌观察及位错组态的衍衬分析，研究无Re镍基单晶合金的蠕变行为与变形机制。结果表明：在760 ℃、750 MPa条件下，合金具有良好的蠕变抗力及较长的蠕变寿命，蠕变期间，合金中的γ′相仅发生粗化，未发生筏形化转变。合金在蠕变初期的变形机制是(1/2) 位错在基体通道的{111}八面体滑移系中运动，蠕变位错可发生单取向滑移、双取向滑移和交滑移；随着蠕变进入后期，合金的应变增大，其变形机制是 位错在基体中运动和剪切进入γ′相，其中，基体中的位错发生扭曲，而部分剪切进入γ′相的 超位错发生分解，形成 肖克莱不全位错+层错的位错组态，可抑制位错的交滑移，使合金具有较好的蠕变抗力。
关键字: 镍基单晶合金；蠕变性能；组织演化；位错组态；变形机制
（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
