(1. 沈阳工业大学 材料科学与工程学院，沈阳 110870； 2. 贵州工程应用技术学院，毕节 551700)
摘 要: 通过对有/无Ru单晶镍基合金进行时效处理、蠕变性能测试及组织形貌观察，研究元素Ru对镍基单晶合金组织结构与蠕变行为的影响。结果表明：加入Ru使合金中元素Co由负偏析转为正偏析，热处理可大幅度降低元素在枝晶干/间的偏析程度。无Ru单晶镍基合金在1080 ℃时效期间沿{111}晶面析出富含难熔元素的针状μ相，而无Ru合金加入2%Ru(质量分数)后，可抑制合金中析出TCP相。与无Ru合金相比，2%Ru合金在980 ℃、200 MPa的蠕变寿命由123 h提高到333 h。合金在蠕变后期的变形机制是位错在基体中滑移和剪切筏状γ′相，其中，主、次滑移位错的交替开动，使其筏状γ′相转变成不规则的扭曲形态。与2%Ru合金相比，无Ru合金中析出大量的针状μ相，可促使裂纹的萌生和扩展，直到蠕变断裂，是使无Ru合金具有较低蠕变抗力和较短蠕变寿命的主要原因。
关键字: 单晶镍基合金；元素Ru；显微组织；TCP相；蠕变；变形特征
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China; 2. Guizhou University of Engineering Science, Bijie 551700, China）
Abstract:By means of aged treatment, creep property measurement and microstructure observation, the influence of element Ru on the microstructure and creep behavior of single crystal nickel-based superalloy was investigated. The results show that the Co is a negative segregation element in Ru-free alloy, whereas adding Ru makes Co transform into positive segregation element. And the segregation extent of elements on the dendrite/inter-dendrite regions may be decreased, to a great extent, by heat treatment. During being aged at 1080 ℃, the slice-like μ phase is precipitated along {111} plane in Ru-free superalloy, and the precipitation of TCP phase may be restrained by adding 2%Ru (mass fraction). Compared to Ru-free alloy, the creep life of the 2%Ru superalloy at 980 ℃, 200 MPa increases form 123 h to 333 h. The deformation mechanism of alloy in the later stage of creep is dislocations slipping in γ matrix and shearing into the rafted g? phase, wherein, the alternate activation of the primary/secondary slipping dislocations results in the twisted of the rafted g? phase to form the irregular configuration. Compared to 2%Ru alloy, the slice-like μ phase precipitated in Ru-free alloy may promote the initiation and propagation of cracks up to fracture, which is thought to be the main reason of the alloy having a lower creep resistances and shorter lifetime.
Key words: single crystal nickel-based superalloy; element Ru; microstructure; TCP phase; creep; deformation feature
