一种镍基单晶合金的组织演化与蠕变行为  

Microstructure evolution and creep behavior of a single crystal nickel-base superalloy

作　　者：夏丹[1] 田素贵[1] 李唐[1] 钱本江[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,沈阳110023

出　　处：《材料与冶金学报》2008年第3期196-200,205,共6页Journal of Materials and Metallurgy

基　　金：国家自然科学基金资助项目(50571070);辽宁省教育厅基金资助项目(2004C004)

摘　　要：通过蠕变曲线测定及组织形貌观察,研究了一种镍基单晶合金的蠕变行为和变形特征.结果表明:单晶合金在试验的温度和应力范围内,对施加应力和温度有明显的敏感性.由所得数据测算出合金的蠕变激活能和应力指数.蠕变初期在施加温度和应力场的作用下,立方γ′相逐渐转变成与施加应力轴方向垂直的N型筏状结构.稳态蠕变期间,合金的变形机制是位错攀移越过筏状γ′相,由于高温蠕变稳态阶段形成的N型γ′相筏状组织厚度较小,位错易于攀移,因而合金具有较大的应变速率.蠕变后期,由于塑性变形,在近断口处筏形γ′相转变成与应力轴方向呈45°角的形貌,合金的变形机制是位错剪切筏状γ′相.By means of the measurement of creep curves and microstructure observation, an investigation has been made into the creep behaviors and deformation features of a single crystal nickel - base superalloy. Results show that, in the range of the applied temperatures and stresses, the single crystal nickel base superalloy displays an obvious sensibility to the applied temperatures and stresses. The cubic γ＇ phase is transformed into the N - type rafted structure along the direction vertical to the applied stress axis during the primary creep. And the dislocation climbing over the γ＇ raft phase is thought to be the deformation mechanism of the alloy during the steady state creep. The dislocation can easily climb over the raft γ＇ phase because of the smaller size of the N-type rafted γ＇ phase in the thickness during the high temperature creep, therefore, the superalloy exhibits a relatively high strain rate. In the later creep stage, the orientation of the γ＇ rafted phase near the fracture regions is transformed into the 45° angle along the direction of the applied stress axis, and the deformation mechanism of the alloy in the tertiary stage of creep is dislocation shearing the rafted γ＇ phase.

关 键 词：单晶镍基合金 组织演化 蠕变行为 变形特征 

分 类 号：TG132.3[一般工业技术—材料科学与工程]