Ni基高温钎料连接SiC陶瓷的微观结构和力学性能  

Microstructure and mechanical properties of SiC/SiC joints brazed with Ni-based high-temperature filler

作　　者：王子康 刘岩[2] 杨金晶[2] 袁明[2] Wang Zikang;Liu Yan;Yang Jinjing;Yuan Ming(School of Meterial and Engineering,Shanghai University,Shanghai 200444,China;Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 200050,China)

机构地区：[1]上海大学材料科学与工程学院,上海200444 [2]中国科学院上海硅酸盐研究所,上海200050

出　　处：《焊接》2023年第2期8-16,共9页Welding & Joining

摘　　要：采用低成本的Ni基高温钎料对SiC陶瓷进行了钎焊连接,通过扫描电镜、能谱分析、透射电镜等测试手段分析了接头的微观结构和物相组成,系统研究了不同钎焊温度和保温时间对SiC/SiC接头力学性能及微观结构的影响规律,分析了不同钎焊工艺参数下制备的SiC/SiC接头断口形貌,阐明了接头宏观力学性能与微观结构之间的对应关系。最后,评价了SiC/SiC接头的高温力学性能。结果表明,SiC/SiC接头由反应区、中心区和基体区3个区域组成,其中反应区主由Ni_(2)Si和不同数量的石墨组成;而中心区主要由复杂碳化物Ni_(3)Mo_(3)C和Ni_(2)Si组成。提高钎焊温度和延长保温时间石墨能够使SiC/SiC接头的反应区厚度增加,生成石墨相的数量也逐渐增多并发生团簇聚集的现象,显著影响了接头的抗弯强度。在1 300℃,40 min条件下,反应区的厚度和石墨的形成量是适宜的,SiC/SiC接头的室温四点抗弯强度最大,达到179 MPa±7 MPa。同时,该接头还具有良好的高温稳定性,在700℃高温下仍能有97.2%的强度保持率,在高温环境中具有可观的应用前景。The low-cost Ni-based high-temperature brazing filler was used for brazing of SiC ceramics.The microstructure and phase composition of the joints were investigated by SEM,EDS,and TEM.The influences of brazing parameters on the mechanical properties and microstructure of SiC/SiC joints were systematically studied.The correspondence between mechanical properties and microstructure of the joints was clarified by analyzing the fracture morphologies of SiC/SiC joints.Finally,the high-temperature mechanical properties of SiC/SiC joints were evaluated.The results showed that the SiC/SiC joint consisted of three regions:the reaction zone,the central zone and the matrix zone.The reaction zone was mainly composed of Ni_(2)Si and different amounts of graphite;while the central zone contained complex carbides Ni_(3)Mo_(3)C and Ni_(2)Si.Increasing the brazing temperature and prolonging the holding time of graphite could rise up the thickness of the reaction zone in the SiC/SiC joints,and a number of graphite phases were formed,which significantly affected the flexural strength of the joints.When the thickness of the reaction zone and the amount of graphite formed were suitable,the maximum flexural strength of 179 MPa±7 MPa was obtained at 1300℃for 40 min.Also,the SiC/SiC joints had good high-temperature stability.When the serving temperature was 700℃,the flexural strength retention rate of 97.2%was obtained,which showed a promising application prospect in high-temperature environments.

关 键 词：SIC陶瓷 Ni基高温钎料 微观结构 抗弯强度 

分 类 号：TG454[金属学及工艺—焊接]