6%Re/5%Ru单晶镍基合金的超高温蠕变行为和影响因素  

Creep behavior and effect factors of 6%Re/5%Ru single crystal nickel-based superalloy at ultra-high temperature

作　　者：赵国旗 田素贵[1,2] 刘丽荣 田宁[2] ZHAO Guo-qi;TIAN Su-gui;LIU Li-rong;TIAN Ning(School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China;School of Mechanical Engineering,Guizhou University of Engineering Science,Bijie 551700,China)

机构地区：[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机械学院,毕节551700

出　　处：《中国有色金属学报》2021年第4期868-878,共11页The Chinese Journal of Nonferrous Metals

基　　金：贵州省科技计划资助项目(黔科合基础[2020]1Y198,黔科合支撑[2019]2870,黔科合平台人才20175502);毕节市科学技术项目(毕科合字[2019]2,毕科合字[2017]05);贵州省高等学校特色重点实验室资助项目(黔教合KY字[2019]053);贵州省科学技术基金资助项目(黔科合LH字[2014]7528)。

摘　　要：通过对6%Re/5%Ru单晶镍基合金(质量分数)进行蠕变性能测试和组织观察,研究了合金的超高温蠕变行为和影响因素。结果表明:测定出合金在(1160℃,120 MPa)的蠕变寿命为206 h。中期稳态阶段,位错在基体中滑移和攀移越过γ′相是合金的变形特征,γ基体中溶解的难熔元素可增加位错在基体中运动的阻力。超高温蠕变期间,随温度提高γ′相发生溶解,可减小筏状γ′相的尺寸,提高位错攀移越过γ′相的速率,特别是当温度大于1170℃时,合金的施加温度敏感性使筏状γ′相的尺寸减小,应变速率提高,这是合金蠕变寿命大幅度降低的主要原因。蠕变后期,基体位错可在位错网破损处切入γ′相,其中,切入γ′相的位错可由{111}面交滑移至{100}面形成K−W锁,抑制位错的滑移和交滑移,可改善合金的蠕变抗力。而在颈缩区域较大的有效应力可开动位错的双取向滑移,致使筏状γ′相扭折,并在扭折区域发生裂纹的萌生和扩展,直至断裂,这是合金在超高温蠕变期间的变形和损伤机制。Through the creep properties test and microstructure observation of a 6%Re/5%Ru single crystal nickel-based superalloy,the ultra-high temperature creep behavior and influencing factors of the alloy were studied.The results show that the creep life of the alloy at(1160℃,120 MPa)is 206 h.The deformation features of alloy in the middle creep period is large number of dislocations sliding inγmatrix and climbing overγ′phase,the refractory elements dissolving inγmatrix may increase the resistance of dislocation movement.During creep at ultra-high temperature,theγ′phase dissolves as the temperature increases,which can reduce the size of the raftedγ′phase and increase the rate of dislocations climbing over the raftedγ′phase.Especially,when the temperature is higher than 1170℃,the applied temperature sensitivity of the alloy diminishes the size of the raftedγ′phase and increases the strain rate,which is the main reason for drastically reducing creep life of the alloy.In the later creep period,the dislocations can shear intoγ′phase from the damaging region of dislocation networks.The K−W locks can be formed by the cross-slip of dislocations from the{111}plane to the{100}plane,which can inhibit the slip and cross-slip of dislocations.The larger effective stress in the necking area can activate the double orientations sliding of dislocations,causing the raftedγ′phase to twist,and crack initiation and propagation in the contorted regions until fracture,which is the mechanism of the deforming and damaging features of alloy during creep at ultra-high temperature.

关 键 词：单晶镍基合金 6.0%Re/5.0%Ru 超高温蠕变 位错网 变形 损伤 K−W锁 

分 类 号：TG115.9[金属学及工艺—物理冶金]