(1. 贵州工程应用技术学院 机械工程学院，毕节 551700； 2. 沈阳工业大学 材料科学与工程学院，沈阳 110870； 3. 中航工业北京航空材料研究院 材料检测与评价航空科技重点实验室 国防科技重点实验室 航空材料检测与评价北京市重点实验室，北京 100095)
摘 要: 通过蠕变性能测试，组织结构观察和晶格常数测定，研究应力时效对 DZ125镍基合金组织演化与蠕变抗力的影响。结果表明：合金在980 ℃、90 MPa近服役条件下的蠕变寿命是9714 h；蠕变期间，样品中间区域的γ′相优先形成完整的筏状组织，在无应力的肩部区域，γ′相呈现串状形态；随应力时效时间延长至9714 h，合金中筏状γ′相的厚度尺寸从0.4 μm增加至1.8 μm，合金中γ′、γ两相的晶格常数值增加，两相的错配度增大。其中，应力时效致使筏状γ′相粗化及错配度增大，可改善蠕变抗力，是合金在近服役条件具有较长蠕变寿命的原因之一。
关键字: DZ125镍基合金；应力时效；蠕变；γ′相粗化；γ′/γ晶格错配度；变形特征
（1. Guizhou University of Engineering Science, Bijie 551700, China; 2. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China; 3. Aviation Key Laboratory of Science and Technology on Materials Testing and Evaluation, Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation, AVIC Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract:By means of creep properties measurement, microstructure observation and parameters measurement, the effects of the stress aging on microstructure evolution and creep resistance of DZ125 nickel-based superalloy were investigated. The results show that the creep life of the alloy at 980 ℃ and 90 MPa near service condition is 9714 h. During creep, the various morphologies of γ′ and γ phases display in different regions of sample. Wherein, the γ′ phase in the middle region of sample firstly transforms into rafted structure, while the γ′ phase in the stress-free region exhibits bunch-like structure. As the time of the stress aging prolongs to 9714 h, the size of the rafted γ′ phase in thickness increases from 0.4 μm to 1.8 μm, which increases the parameters and misfits of γ′ and γ phases in the alloy. The deformation mechanisms of alloy during steady state creep are dislocations slipping in the matrix channels and climbing over the rafted γ′ phase. In the later stage of creep, the deformation mechanisms of alloy are dislocations shearing into the rafted γ′ phase. Wherein, the fact that the stress aging results in the coarsening of γ′/γ′ phases to increase the misfits may improve the creep resistance of the alloy, which is thought to be one of the reasons of the alloy with a longer creep lifetime.
Key words: DZ125 nickel-based superalloy; stress aging; creep; γ′ phase coarsening; misfit; deformation feature
