NiCoCrAlY/YSZ梯度涂层热力学性能的有限元模拟  

Finite element simulation of thermodynamic properties of NiCoCrAlY/YSZ gradient coating

作　　者：王士峰 夏明岗[2] 刘明 王玉[1] 王斌[2] 白宇[1] 王海斗[3] WANG Shifeng;XIA Minggang;LIU Ming;WANG Yu;WANG Bin;BAI Yu;WANG Haidou(State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China;School of Physics,MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter,Xi’an Jiaotong University,Xi’an 710049,China;National Key Laboratory for Remanufacturing,Army Academy of Armored Forces,Beijing 100072,China)

机构地区：[1]西安交通大学金属材料强度国家重点实验室,西安710049 [2]西安交通大学物理学院物质非平衡合成与调控教育部重点实验室,西安710049 [3]陆军装甲兵学院装备再制造技术国防科技重点实验室,北京100072

出　　处：《航空材料学报》2023年第1期70-79,共10页Journal of Aeronautical Materials

基　　金：国家自然科学基金重点项目(52130509);国家自然科学基金面上项目(52075542);国家自然科学基金青年项目(52005388)。

摘　　要：采用代表体积单元法建立NiCoCrAlY/YSZ梯度热障涂层的有限元二维微观模型,计算不同相成分配比下梯度层的热物理性能参数,将参数结果推广到三维多层涂层实体模型,研究热循环过程中双层结构涂层和梯度结构涂层的热力学性能。结果表明:梯度层的弹性模量、泊松比、热膨胀系数、导热系数与各相成分比例近似呈线性关系,导热系数受各相分布形态的影响;当梯度层中NiCoCrAlY相成分比例在0.7以下时,导热系数较低,常温状态最高为2.91 W·m^(-1)·K^(-1)。相比于双层结构涂层,梯度结构涂层的YSZ成分比例降低20%,隔热温度降低14%,陶瓷面层在高温时产生的热失配径向拉应力降低47%,轴向拉应力降低32%,切应力降低37%,冷却后的残余应力降低50%,这归因于涂层结构的梯度化有效降低涂层与基体热膨胀系数不同而产生的热失配应力。根据涂层应力分布结果,涂层易在TC/BC界面的中心区域形成垂直裂纹,靠近外侧边缘区形成水平裂纹。The two-dimensional finite element microscopic model of NiCoCrAlY/YSZ gradient thermal barrier coating was established by using the representative volume element method to calculate the thermophysical properties of the gradient layer under different composition ratios.The parameter results were extended to the three-dimensional multi-layer solid model to study the thermodynamic properties of the double-layer coating and gradient structured coating under thermal cycling condition.The results show that the elastic modulus,Poisson’s ratio,coefficient of thermal expansion and thermal conductivity of the gradient layer are approximately linear with the component proportion of each phase,and the thermal conductivity is also affected by the distribution pattern of each phase.The thermal conductivity is low and the highest value is 2.91 W·m^(-1)·K^(-1) when the proportion of NiCoCrAlY phase in the gradient layer is below 0.7 at room temperature.Compared with the double-layer coating,the proportion of YSZ in gradient coatings is reduced by 20%,the insulation temperature is reduced by 14%,the radial tensile stress,axial tensile stress,and shear stress of the ceramic surface layer at high temperature are reduced respectively by 47%,32% and 37%,and the residual stress after cooling is reduced by 50%.The results are attributed that the gradient of the coating structure can effectively reduce the thermal mismatch stress caused by the difference in the thermal expansion coefficient between coating and substrate.According to the results of coating stress distribution,the coating is inclined to form vertical cracks in the centre region and horizontal cracks near the outer edge of the TC/BC interface.

关 键 词：热障涂层 梯度结构 有限元 微观模型 热应力 

分 类 号：TG148[一般工业技术—材料科学与工程]