激光熔覆镍基高温耐磨合金的组织及性能  

Microstructure and Properties of Laser Cladding Ni-based High-temperature Wear-resistant Alloy

作　　者：李胜[1] 雷远涛 伍文星 申龙章 陈勇[1] 朱红梅 邱长军[1] LI Sheng;LEI Yuantao;WU Wenxing;SHEN Longzhang;CHEN Yong;ZHU Hongmei;QIU Changjun(Hunan Provincial Key Laboratory of Equipment Safety Service Technology under Abnormal Environment,University of South China,Hengyang 421001,China)

机构地区：[1]南华大学超常环境下装备安全服役技术湖南省重点实验室,衡阳421001

出　　处：《中国表面工程》2023年第5期213-221,共9页China Surface Engineering

基　　金：国防科技重点实验室基金(JCKY61420052002);中央军委装备发展部装备预研基金(61400040204);湖南省研究生科研创新(223YSC009)资助项目。

摘　　要：通过增加IN718合金中(Ti+Al)含量制备一种镍基高温耐磨合金,以满足超临界机组镍基合金阀门密封面再制造的需求。采用万能试验机、摩擦磨损试验机、XRD、SEM等仪器和JMatpro软件研究该合金激光熔覆试样的组织与性能。研究结果如下:当IN718合金的(Ti+Al)含量增加至7.6%时熔覆层会出现开裂;当IN718合金的(Ti+Al)含量增加至6.6%时,其激光熔覆试样初始平均硬度值为40 HRC,抗拉强度为998 MPa,延伸率为5.2%,室温摩擦因素为0.75左右,磨损量为0.3275 mm^(3),主相为γ相和γ′相,700℃×10 h时效处理后平均硬度值为54 HRC,700℃摩擦因素为0.35左右,磨损量为0.024 mm^(3),主相γ′占53%。研究结果表明,IN718合金中(Ti+Al)含量增加至6.6%时具有良好的激光熔覆工艺性能和高温摩擦磨损性能,可应用于超临界/超超临界机组镍基合金阀门密封面的维修与再制造。IN718 is a nickel-based high-temperature alloy with economic performance that is widely used in manufacturing of hot-end components with ambient temperatures not exceeding 650℃.Its structural composition includes the γ phase as the matrix;the γ″phase is the main strengthening phase and theγ′phase is an auxiliary strengthening phase.In response to the insufficient high-temperature wear-resistance of the nickel-based alloy valve-sealing surface of generator units operating in supercritical/ultra-supercritical environments,two improved nickel-based high-temperature wear-resistant alloy powders were prepared based on IN718 alloy by increasing its(Ti+Al)content to 6.6% and 7.6% to improve performance.The proportion of γ′precipitate phases and some brittle and hard phases greatly improve the high-temperature wear-resistance of the alloy,meeting the manufacturing and remanufacturing requirements of nickel-based alloy valve-sealing surfaces in supercritical units.A nickel-based high-temperature wear-resistant alloy sample was prepared on 304 stainless steel substrate using laser cladding deposition technology.The room temperature tensile properties of the sample were tested using a universal testing machine.The wear resistance of the sample with(Ti+Al)content up to 6.6% was tested by a high-temperature friction and wear testing machine at room temperature and 700℃.The microstructure of the IN718im2 laser cladding sample was studied using XRD and SEM.The phase proportions in IN718 and IN718im2 were calculated using JMatpro software.The results are presented as follows.When the(Ti+Al)content of IN718 alloy was increased to 7.6%,a large transverse crack appeared in the cladding layer.At this point,the SEM morphology of the sample surface showed a large number ofδphases and other brittle phases.The hardness values of the IN718im2 sample before and after heat treatment were 41.22 HRC and 55.6 HRC,respectively.When the(Ti+Al)content of IN718 alloy was increased to 6.6%,the initial average hardness of the laser c

关 键 词：激光熔覆 镍基高温合金 摩擦磨损 阀门密封面 组织结构 

分 类 号：TG115[金属学及工艺—物理冶金] TB114[金属学及工艺—金属学]