Abstract:An elasticplastic finite element numerical model for gradient coatings with sandwich structure was formulated to study Mises stresses distribution at Al2O3 gradient ceramic coatings during contact load.The influence of structure parameters such as the layout of interlayer/metal,the thickness of gradient coatings on the Mises stress distribution and the position of maximum Mises stress was analyzed.The results show that the gradient structure has less influence on the size and distribution of Mises stress,while has some influence on the position of the maximum Mises stress.The reasonable gradient structure can avoid the maximum Mises stress to appear in the surface hardening zone and the gradient zone,and can prevent the ceramic coating from falling off under the contact load.A gradient structure with Al2O3 layer thickness of 20 μm,linear gradient layer thickness of 80 μm and 8 interlayers was proposed,which can improve the Mises stress,and avoid the maximum Mises stress to appear in the gradient area properly.