(沈陽工業(yè)大學 材料科學與工程學院，沈陽 110870)
摘 要: 通過對不同溫度固溶處理合金枝晶干/間區(qū)域進行成分分析、蠕變性能測試及組織形貌觀察，研究固溶溫度對一種無Re單晶鎳基合金成分偏析和蠕變行為的影響。結(jié)果表明：經(jīng)不同溫度固溶處理后，合金中枝晶干/間區(qū)域具有不同的偏析程度，隨固溶溫度提高，元素偏析程度降低，可明顯提高合金的蠕變抗力和延長蠕變壽命。800 ℃蠕變期間，合金中γ′相僅形成串狀結(jié)構(gòu)，未形成完全筏狀組織。合金在中溫蠕變期間的變形機制是位錯在基體中滑移和剪切γ′相，其中，在基體中發(fā)生大量位錯的單取向、雙取向滑移，可產(chǎn)生形變硬化作用，阻礙位錯運動，加之γ′/γ兩相共格界面的應力場作用，可抑制位錯剪切進入γ′相，是使合金在穩(wěn)態(tài)蠕變期間保持較低應變速率的主要原因。
關(guān)鍵字: 單晶高溫合金；成分偏析；固溶熱處理；蠕變；變形機制
（School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China）
Abstract:By means of solution treatment at various temperatures, creep properties measurement and microstructure observation, the effects of heat treatment on the composition segregation and creep properties of a single crystal nickel-based superalloy were investigated. The results show that the various segregation extents of the elements display in the interdendrite/dendrite regions of the alloy solution-treated at different temperatures, and the segregation extent of the elements is improved with the increase of the solution temperature, which may obviously improve the creep resistance and prolong the creep life of the alloy. During the creep at 800 ℃, the γ′ phase in the alloy only forms bunch-like structure, and no fully rafting structure forms. The deformation mechanisms of the alloy during creep at intermediate temperature/higher stress are the dislocations slipping in the matrix and shearing into γ′ phase. Thereinto, significant amount of dislocations with single oriented and double oriented slipping features activated in the γ matrix may hinder dislocation motion due to the effect of deformation strengthening, and the stress field effect in the coherent interface of γ′/γ phase can restrain dislocation shearing into γ′ phase, which is thought to be the main reason why the alloy keeps a lower strain rate during steady state creep.
Key words: single crystal superalloy; composition segregation; solution treatment; creep; deformation mechanism
