钼合金MoSi_2涂层高温热震行为与裂纹扩展  

Thermal Shock Behavior and Crack Propagation of MoSi_2 Coating on Molybdenum Alloy

作　　者：肖来荣[1,2] 张贝[1] 蔡圳阳[1,2] 孙国基 李威 刘建飞[1] 朴晟铭 Xiao Lairong;Zhang Bei;Cai Zhenyang;Sun Guoji;Li Wei;Liu Jianfei;Piao Shengming(Central South University,Changsha 410083,China;Key Laboratory of Nonferrous Metals Materials Science and Engineering,Ministry of Education,Changsha 410083,China)

机构地区：[1]中南大学,湖南长沙410083 [2]有色金属材料科学与工程教育部重点实验室,湖南长沙410083

出　　处：《稀有金属材料与工程》2018年第11期3387-3392,共6页Rare Metal Materials and Engineering

基　　金：国家科技重大专项(0101040201);国家自然科学基金重点项目(U1637210);中南大学创新驱动计划项目(51271203);国家级大学生自由探索创新实验项目(201610533388)

摘　　要：采用料浆烧结法在钼合金表面制备了MoSi_2涂层,利用内热法测试了涂层室温～1600℃抗热震性能,通过扫描电镜(SEM)、电子探针(EPMA)、波谱分析(WDS)和X射线衍射(XRD)仪等测试手段分析了不同热震次数的涂层微观形貌、组织结构以及裂纹萌生扩展。结果表明:涂层可承受室温～1600℃热震400次,热震过程中涂层由原始的MoSi_2-Mo5Si_3双层结构演变为SiO_2-MoSi_2-Mo5Si_3多层结构,涂层热震初期形成纵向裂纹并不断向基体扩展,热震后期裂纹贯穿涂层到达基体,MoO_3挥发使涂层/基体界面应力增大产生横向裂纹,导致涂层剥落失效。An adherent MoSi2 coating on Mo-based alloy was prepared by a fused slurry method.The thermal shock resistance of the coating was evaluated by cycle tests from room temperature to 1600℃ in air.Besides,the microstructures,morphology and crack propagation of the coating were analyzed by SEM,EPMA,WDS and XRD.The results show that the coating can withstand thermal shock of 400 times from room temperature to 1600℃.During the oxidizing process,the coating evolves from the original MoSi2-Mo5Si3 bilayer structure into SiO2-MoSi2-Mo5Si3 multilayer structure.At the initial stage of the thermal shock,the longitudinal cracks are formed and gradually extend to the substrate,and run through the coating at the later thermal shock stage.In the meantime,the volatilization of MoO3 increases the stress of the interface of coating/substrate to cause transverse cracks,resulting in the spalling and failure of the coating.

关 键 词：钼合金 硅化物涂层 MOSI2 热震 裂纹扩展 

分 类 号：TG174.44[金属学及工艺—金属表面处理]