Re含量对DD15单晶高温合金显微组织和持久性能的影响  

Effect of Re Content on Mircrostructure and Stress Rupture Properties of DD15 Single Crystal Superalloy

作　　者：史振学[1] 刘世忠[1] 岳晓岱[1] 王志成 李嘉荣[1] Shi Zhenxue;Liu Shizhong;Yue Xiaodai;Wang Zhicheng;Li Jiarong(Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]北京航空材料研究院先进高温结构材料重点实验室,北京100095

出　　处：《稀有金属材料与工程》2023年第6期1977-1984,共8页Rare Metal Materials and Engineering

基　　金：National Science and Technology Major Project(2017-Ⅵ-0002-0071,J2019-Ⅲ-0008-0052)。

摘　　要：在定向凝固炉中制备了3种不同Re含量(5%,6%,7%,质量分数)、其它合金元素相同的第4代单晶高温合金DD15,将其完全热处理后在1100℃长期时效1000 h,在1100℃/137 MPa条件下测试合金的持久性能。研究了Re含量对DD15单晶高温合金组织稳定性和持久性能的影响。结果表明,随着Re含量增加,γ′相尺寸减小,其体积分数和立方化程度稍有增加,长期时效时γ′相粗化、筏排化速率和TCP相析出量增加,合金的组织稳定性降低。合金的持久性能随着Re含量增加而显著降低。3种断裂试样中均发现了TCP相,其含量随着Re含量增加而增多,这是合金持久性能随Re含量增加而降低的主要原因。γ/γ′相界面位错网密度随着Re含量增加而增加。Re元素在γ基体中有强烈的偏析倾向,分配比随Re含量增加而显著升高。随着Re含量增加,合金的晶格错配度向负方向增加。The fourth generation single crystal superalloy DD15 with Re content of 5wt%,6wt%,and 7wt%was cast in the directionally solidified furnace,while other alloying elements were basically the same in content.The long term aging after full heat treatment was performed at 1100℃ for 1000 h.The stress rupture tests of the alloy were conducted under 1100℃/137 MPa.The effect of Re content on the microstructure and stress rupture properties of the alloy was investigated.The results show that the size ofγ′phase decreases,the volume fraction and cubic degree ofγ′phase slightly increase with increase in Re content.After long term aging,theγ′phase coarsens,and the drafting rate,precipitate rate and volume fraction of TCP phase are all improved with increase in Re content.With the increase in Re content,the microstructure stability and the stress rupture life of the alloy decline significantly.The three ruptured specimens all exhibit the presence of TCP phase.The amount of TCP phases increases greatly with increase in Re content.TCP phase can be the site of crack initiation.This is the main reason for the decrease in stress rupture life of the alloy with increase in Re content.The dislocation networks formed at theγ/γ′interface of ruptured specimen turn denser with increase in Re content.Re has a strong segregation tendency inγmatrix.The partition ratio of Re rises significantly with increase in Re content.The lattice misfit of the alloy becomes larger toward negative with increase in Re content.

关 键 词：单晶高温合金 DD15 Re含量 持久性能 

分 类 号：TG132.3[一般工业技术—材料科学与工程]