(1. 貴州工程應用技術學院 機械工程學院，畢節(jié) 551700； 2. 沈陽工業(yè)大學 材料科學與工程學院，沈陽 110870； 3. 中航工業(yè)北京航空材料研究院 材料檢測與評價航空科技重點實驗室 國防科技重點實驗室 航空材料檢測與評價北京市重點實驗室，北京 100095)
摘 要: 通過蠕變性能測試，組織結構觀察和晶格常數(shù)測定，研究應力時效對 DZ125鎳基合金組織演化與蠕變抗力的影響。結果表明：合金在980 ℃、90 MPa近服役條件下的蠕變壽命是9714 h；蠕變期間，樣品中間區(qū)域的γ′相優(yōu)先形成完整的筏狀組織，在無應力的肩部區(qū)域，γ′相呈現(xiàn)串狀形態(tài)；隨應力時效時間延長至9714 h，合金中筏狀γ′相的厚度尺寸從0.4 μm增加至1.8 μm，合金中γ′、γ兩相的晶格常數(shù)值增加，兩相的錯配度增大。其中，應力時效致使筏狀γ′相粗化及錯配度增大，可改善蠕變抗力，是合金在近服役條件具有較長蠕變壽命的原因之一。
關鍵字: DZ125鎳基合金；應力時效；蠕變；γ′相粗化；γ′/γ晶格錯配度；變形特征
（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
