铝合金表面等离子喷涂Mo/8YSZ复合涂层残余应力的数值模拟

Numerical simulation of residual stress of plasma sprayed Mo/8YSZ composite coatings on aluminum alloy surface

为了突破传统热障涂层高温易剥落的技术瓶颈,基于ANSYS有限元仿真模拟软件"生死单元"的方法,建立了铝合金表面等离子喷涂Mo/8YSZ复合涂层的有限元模型,模型中考虑了材料热物性参数随温度的变化,分析了不同配比的金属钼和8%氧化钇部分稳定氧化锆复合涂层残余应力的变化规律。结果表明:随着复合涂层中金属钼比例的减小,喷涂构件的最大径向残余拉应力、最大轴向残余应力和最大剪残余应力减小,最大径向残余压应力和最大剪残余压应力增大;在距离涂层与基体界面边缘0. 5 mm处和距离涂层与基体界面边缘下方0. 04 mm处,存在着与其他区域相比更大的应力突变,且随着金属钼比例的减小,应力突变值逐渐减小;改变涂层材料的复合配比对基体与涂层界面边缘位置的残余应力影响更为显著;通过合理调控复合涂层材料配比,可实现喷涂构件的最佳应力分布状态,提升涂层的结合强度。

In order to break through the technical bottleneck of high temperature spalling of traditional thermal barrier coating,the finite element model of plasma sprayed Mo /8YSZ composite coatings on aluminum alloy surface was established based on the method of“life and death unit”of ANSYS finite element simulation software. The variation of thermal physical parameters of materials with temperature was taken into account in the model,and the variation of residual stress of metal molybdenum and 8YSZ composite coatings with different ratios of Mo was analyzed. The results show that with the decrease of Mo ratio in the composite coatings,the maximum radial residual tensile stress,the maximum axial residual stress and the maximum shear residual stress of the sprayed component decrease,and the maximum radial residual compressive stress and the maximum shear residual compressive stress increase. At 0. 5 mm away from the interface edge between the coatings and the substrate and 0. 04 mm below the interface edge between the coatings and the substrate,there is a greater stress mutation than that in other regions,and with the decrease of the ratio of Mo,the stress mutation value decreases gradually. Changing the composite ratio of the coatings material has a more significant effect on the residual stress at the edge of the interface between the substrate and the coatings. By reasonably adjusting the ratio of the composite coatings material,the optimum stress distribution state of the spraying component can be realized and the bonding strength of the coatings can be improved.