有限元探究表面曲率和基体厚度对等离子喷涂层残余应力影响

Study of the effect of substrate surface curvature and thickness on residual stress of plasma sprayed coatings by finite element method

为探究基体表面曲率和基体厚度对等离子喷涂涂层残余应力的影响,文章建立不同表面曲率和基体厚度的模型,应用有限元方法,在控制喷涂工艺参数不变的情况下,对不同模型进行TC4钛合金表面喷涂NiCrAl涂层的仿真。结果表明,基体表面曲率及基体厚度均不会影响残余应力的整体分布规律,而对其大小有影响。涂层与基体结合面上残余应力分布呈边缘位置应力大,而中心位置上较小的规律。当基体表面曲率κ从0 mm^(-1)增加到1/9 mm^(-1)时,结合面边缘位置的残余应力值降低明显。在基体表面曲率相同的情况下,基体厚度增大可使结合面上残余应力极值明显降低。在文章的参数选择范围内,增大基体表面曲率、增加基体厚度均可减小结合面上的等效残余应力的极值,有助于提高涂层与基体的结合质量。

In order to investigate the effect of substrate surface curvature and thickness on the residual stress of plasma sprayed coatings,this paper established models with different substrate surface curvatures and thicknesses,and applied the finite element method to carry out the simulation on the different models for spraying NiCrAl coatings on TC4 titanium alloy surfaces under the control of constant spraying process parameters.The results show that the curvature of the substrate surface and the thickness of the substrate do not affect the overall distribution pattern of the residual stress,but have an effect on its magnitude.The distribution of residual stress on the bonding surface of the coating and the substrate shows a pattern of high stress at the edges and low stress at the center.When the substrate surface curvatureκincreases from 0 mm^(-1) to 1/9 mm^(-1),the larger residual stress values on the bonding surface decrease significantly.In the case of the same curvature of the substrate surface,an increase in the substrate thickness can result in a significant decrease in the extreme value of the residual stress on the bonding surface.In the range of parameters selected in this paper,increasing the substrate surface curvature and the substrate thickness can reduce the equivalent residual stress extremes on the bonding surface and help improve the bonding quality of the coating and the substrate.