Sm2Ce2O7/YSZ功能梯度热障涂层的残余热应力

目的研究基体材质、厚度及半径对Sm_2Ce_2O_7/YSZ功能梯度热障涂层残余热应力的影响。方法采用ANSYS10.0软件中Plane13单元,通过直接耦合计算,系统分析了不同基体条件下,Sm_2Ce_2O_7/YSZ功能梯度热障涂层的残余热应力。结果在Sm_2Ce_2O_7/YSZ功能梯度热障涂层中存在较大的残余热应力。涂层残余热应力随时间的增加而逐渐降低,900 s后基本维持稳定。涂层径向热应力从中心处到试样边缘逐渐递减。2Cr13对应的涂层应力最小。金属基体厚度在2~10 mm范围内,径向热应力虽然增加,但变化幅度不大。当基体厚度为20 mm时,涂层径向热应力则显著增加。金属基体半径对涂层的最大剪切应力并不产生影响,轴向热应力随基体半径的增加而逐渐降低,径向热应力随半径增加到一定值后趋于稳定。结论 2Cr13钢基体对应的涂层具有最小热应力,基体厚度为10 mm时比较合适,基体半径对涂层轴向热应力的影响最明显。

Residual Thermal Stress of Sm2Ce2O7/YSZ Functional Graded Thermal Barrier Coatings

The work aims to study effects of substrate material, thickness and radius on residual thermal stress of Sm2Ce2O7/YSZ functional graded thermal barrier coatings. By using Plane 13 element in ANSYS10.0 software and directional coupling calculation, the residual thermal stress of Sm2Ce2O7/YSZ functional graded thermal barrier coatings under different substrate conditions was analyzed systematically. Higher residual thermal stresses were present in the coatings. The residual thermal stress gradually decreased as increasing time prolonged, and basically stayed at stable value after 900 s. Radial stress of the coatings reduced from sample center to edges, and coating stress of 2Cr13-coating was the smallest. The radial thermal stress of the coatings was relative stable as metallic substrate thickness ranged from 2 to 10 mm, and increased significantly as metallic substrate thickness was 20 mm. Radius of the substrate had no effect on maximum shear stress of the coatings, axial stress decreased gradually as substrate radius increased, and the radial thermal stress tended to be stable as it reached a certain value. The 2Cr13-steel coating has the lowest residual thermal stress, appropriate substrate thickness is 10 mm, and the substrate radius has the most obvious effect on axial thermal stress.