轴类件热喷涂涂层残余应力的有限元分析

热喷涂涂层内部的残余应力分布是影响喷涂成形质量和使用性能的重要因素之一.文中基于热喷涂过程的逐层叠加成形的基本假设,利用有限单元法建立了轴类金属基体表面沉积铝涂层的温度场和应力场二维数值模型,研究结果揭示了喷涂涂层温度的波动上升和大量粒子独立快速凝固的典型规律,通过分析残余应力分布行为,发现涂层内部的周向和轴向应力分量最大,皆为拉应力；径向应力分量值远小于周向和轴向应力,应力方向不固定.当涂层不断增厚时,每一薄层的应力受后续沉积薄层的作用发生部分抵消,且残余应力分量值都随着涂层厚度的增加而增大.

Analysis of FEA of residual stress for thermal sprayed coating on shaft parts

The distribution of residual stresses within the thermal sprayed coating is one of the important factors affecting the quality and performance of the coating. In this paper,based on the assumption of layer-by-layer forming during thermal spraying process,a two-dimensional numerical model was proposed to analyze the temperature and stress fields for aluminum coating deposited on a metallic shaft part substrate. The simulation results show that a wave-like rise of the temperature in the coating occurred and a great amount of hot particles individually cooled rapidly. The distribution of residual stresses in the coating was also investigated,and it was found that the circumferential and axial stresses are tensile and far higher than that of the radial stress,while the radial stress could be tensile or compressive. As the spraying was proceeding and the coating was thickening, the residual stress on the deposited layer was partly offset by the followed layers,and the components of the residual stresses increased with the coating thickness.