新型铁镍基高温合金的700℃蠕变性能及组织演变  

Creep property and microstructure evolution at 700℃of a novel Fe-Ni based superalloy

作　　者：焦春晖 潘艳君 李生志 白笃 李备 邓阁 贾晓帅[1,4] Jiao Chunhui;Pan Yanjun;Li Shengzhi;Bai Du;Li Bei;Deng Ge;Jia Xiaoshuai(School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Baotou North Safety Equipment Manufacturing Co.,Ltd.,Baotou Inner Mongolia 014030,China;Shanghai Turbine Plant,Shanghai Electric Power Station Equipment Co.,Ltd.,Shanghai 200240,China;Inner Mongolia Research Institute,Shanghai Jiao Tong University,Hohhot Inner Mongolia 010052,China;Shanghai Construction Machinery Testing Center Co.,Ltd.,Shanghai 200137,China)

机构地区：[1]上海交通大学材料科学与工程学院,上海200240 [2]包头北方安全防护装备制造有限公司,内蒙古包头014030 [3]上海电气电站设备有限公司上海汽轮机厂,上海200240 [4]上海交通大学内蒙古研究院,内蒙古呼和浩特010052 [5]上海市建设机械检测中心有限公司,上海200137

出　　处：《金属热处理》2025年第2期1-7,共7页Heat Treatment of Metals

基　　金：国家重点研发计划(2023YFB4102300);科技兴蒙上海交通大学行动计划专项(2023XYJG0001-01-01)。

摘　　要：以超超临界火力发电机组用新型铁镍基高温合金为研究对象,在700℃开展不同应力(250、200 MPa)下的恒载蠕变试验,对其服役极限及服役寿命进行预判,并对蠕变过程组织演变进行分析。结果表明,在700℃/250 MPa与700℃/200 MPa两种蠕变条件下,试验合金的蠕变寿命分别为2378 h和12716 h,结合Larson-Miller方程外推出该合金在700℃分别蠕变100000 h和260000 h时,可承受的载荷约为152 MPa和134 MPa,完全满足服役要求(应力35 MPa、蠕变寿命100000 h)。组织表征发现,700℃/250 MPa试样组织中分布有高密度位错,而700℃/200 MPa试样中的位错分布较少;晶粒内部尺寸较大的MC碳化物主要为块状或棒状,在更高的应力状态下,MC碳化物的长大速度更快;晶界处尺寸较小的M_(23)C_(6)碳化物主要以链状形式析出,随蠕变时间的增加,M_(23)C_(6)碳化物的宽度增加;晶粒内部的γ′相始终呈球状,蠕变过程中发生粗化,部分晶界处的γ′相异常长大,形成不利于合金高温蠕变性能的PFZs/DCZs。A novel Fe-Ni-based superalloy,intended for ultra-supercritical thermal power generating units,was evaluated under constant load conditions at 700℃with varying stress levels of 250 MPa and 200 MPa.The service limit and creep life of the alloy were predicted,and the microstructure evolution during creep was analyzed.The results indicate that the creep life of the alloy at 700℃/250 MPa and 700℃/200 MPa is 2378 h and 12716 h,respectively.Based on the Larson-Miller equation,the alloy can withstand stresses of approximately 152 MPa after 100000 h and 134 MPa after 260000 h at 700℃,fully meeting the service requirements(stress of 35 MPa,creep life of 100000 h).Microstructure analysis reveals that high-density dislocations are distributed in the 700℃/250 MPa specimen,whereas fewer dislocations are observed in the 700℃/200 MPa specimen.The MC carbides with larger size within the grains predominantly exhibit blocky or rod-like morphologies,with faster growth rates under higher stress conditions.The smaller M_(23)C_(6)carbides at grain boundaries precipitate primarily in chain form,and their width increases with prolonged creep exposure.Theγ′phase within the grains remains spherical but undergoes coarsening during creep.Notably,some grain boundaryγ′phases exhibit abnormal growth,forming PFZs/DCZs,which adversely affect the alloy's high-temperature creep performance.

关 键 词：新型铁镍基高温合金 高温蠕变性能 蠕变寿命预判 组织表征 

分 类 号：TG113.25[金属学及工艺—物理冶金]