Ru对镍基单晶合金组织结构与蠕变行为的影响  

Influence of element Ru on microstructure and creep behavior of single crystal nickel-based superalloy

作　　者：田素贵[1] 朱新杰 田宁 李秋阳[1] 梁爽[1] 

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,毕节551700

出　　处：《中国有色金属学报》2018年第2期275-284,共10页The Chinese Journal of Nonferrous Metals

摘　　要：通过对有/无Ru单晶镍基合金进行时效处理、蠕变性能测试及组织形貌观察,研究元素Ru对镍基单晶合金组织结构与蠕变行为的影响。结果表明:加入Ru使合金中元素Co由负偏析转为正偏析,热处理可大幅度降低元素在枝晶干/间的偏析程度。无Ru单晶镍基合金在1080℃时效期间沿{111}晶面析出富含难熔元素的针状μ相,而无Ru合金加入2%Ru(质量分数)后,可抑制合金中析出TCP相。与无Ru合金相比,2%Ru合金在980℃、200 MPa的蠕变寿命由123 h提高到333 h。合金在蠕变后期的变形机制是位错在基体中滑移和剪切筏状γ′相,其中,主、次滑移位错的交替开动,使其筏状γ′相转变成不规则的扭曲形态。与2%Ru合金相比,无Ru合金中析出大量的针状μ相,可促使裂纹的萌生和扩展,直到蠕变断裂,是使无Ru合金具有较低蠕变抗力和较短蠕变寿命的主要原因。By means of aged treatment, creep property measurement and microstructure observation, the influence of element Ru on the microstructure and creep behavior of single crystal nickel-based superalloy was investigated. The results show that the Co is a negative segregation element in Ru-free alloy, whereas adding Ru makes Co transform into positive segregation element. And the segregation extent of elements on the dendrite/inter-dendrite regions may be decreased, to a great extent, by heat treatment. During being aged at 1080 ℃, the slice-like μ phase is precipitated along {111} plane in Ru-free superalloy, and the precipitation of TCP phase may be restrained by adding 2%Ru（mass fraction）. Compared to Ru-free alloy, the creep life of the 2%Ru superalloy at 980 ℃, 200 MPa increases form 123 h to 333 h. The deformation mechanism of alloy in the later stage of creep is dislocations slipping in γ matrix and shearing into the rafted γ＇ phase, wherein, the alternate activation of the primary/secondary slipping dislocations results in the twisted of the rafted γ＇ phase to form the irregular configuration. Compared to 2%Ru alloy, the slice-like μ phase precipitated in Ru-free alloy may promote the initiation and propagation of cracks up to fracture, which is thought to be the main reason of the alloy having a lower creep resistances and shorter lifetime.

关 键 词：单晶镍基合金 元素Ru 显微组织 TCP相 蠕变 变形特征 

分 类 号：TG111.8[金属学及工艺—物理冶金]