基于相场法的高温烧结条件下等离子喷涂热障涂层微结构演化模拟  

Simulation of Microstructure Evolution of Plasma-Sprayed Thermal Barrier Coatings During High-Temperature Sintering Based on Phase Field Method

作　　者：谭振宇 杨紫涵 朱旺 杨丽 周益春 TAN Zhen-yu;YANG Zi-han;ZHU Wang;YANG Li;ZHOU Yi-chun(Key Laboratory of Key Film Materials & Application for Equipment, School of Materials Science and Engineering, Xiangtan University,Xiangtan 411105;Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education,School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 China)

机构地区：[1]湘潭大学材料科学与工程学院,装备用关键薄膜材料及应用湖南省国防科技重点实验室,湖南湘潭411105 [2]湘潭大学材料科学与工程学院,低维材料及其应用技术教育部重点实验室,湖南湘潭411105

出　　处：《湘潭大学学报（自然科学版）》2020年第3期82-89,共8页Journal of Xiangtan University(Natural Science Edition)

基　　金：国家自然科学基金项目(51590891,11890684,51672233)。

摘　　要：为提高航空发动机性能,热障涂层被广泛地用于涡轮叶片上.涂层在高温下服役时,会发生烧结,使涂层变得更加致密,从而不可避免地增加了热障涂层的弹性模量和热导系数,强烈地影响了涂层的耐用性、效率和性能.该文针对等离子喷涂制备的热障涂层,建立了涂层的二维真实微结构有限元模型,并运用相场模型研究了在1400℃烧结条件下涂层微结构随时间演化的动态规律.计算结果表明:在烧结初期,涂层中微裂纹在最窄处迅速愈合,并开始形成不连续的单个小孔隙.烧结中期,前期由微裂纹产生的孔隙不断愈合,或者与相邻孔隙合并.烧结后期,涂层前期微裂纹大都形成了球形,孔隙间相对距离大,较小孔隙主要是以愈合的方式消失,涂层孔隙率随烧结时间的增加先迅速下降后趋于平稳.模拟的结果与实验结果相吻合.Thermal barrier coatings are widely used on turbine blades to improve engine performance.When the coating is in service at high temperature,sintering occurs,which makes the coating more compact and inevitably increases the elastic modulus and thermal conductivity of the thermal barrier coating,which strongly affects the durability,efficiency and performance of the coating.In this paper,a two-dimensional real microstructure finite element model of thermal barrier coatings prepared by plasma spraying is established,and the dynamic evolution of microstructure with time under the sintering condition of 1400℃is studied by using the phase field model.The results show that the micro-cracks heal rapidly at the narrowest point in the initial sintering stage and begin to form a discontinuous single pore.During the middle stage of sintering,it is obvious that the pores generated by micro-cracks in the early stage of sintering are healing continuously,or are swallowed by adjacent pores.At the later stage of sintering,most of the micro-cracks in the early stage of the coating formed spherical,and the relative distance between the pores was large.The smaller pores disappeared mainly by healing.The porosity of the coating decreased rapidly at first and then stabilized with the increase of sintering time.The simulation results are in good agreement with the experimental results.

关 键 词：热障涂层 相场法 真实微结构 烧结 

分 类 号：V261.93+3[航空宇航科学与技术—航空宇航制造工程]