The need for more components that are more resistant to wear and corrosion has promoted a growing interest in surface engineering. The search for improved tribological properties in materials contributes to the development of processes that extend the useful life of components and their applications in increasingly severe environments. In this respect, thin ceramic coatings have been used to enhance the tribological properties of components that operate under these conditions. However, new experimental assays are needed to assess the behaviour of these films and their surface as substrate. These experimental analyses require the use of sophisticated equipment and specialized personnel. On the other hand, with advances in computational mechanics, the application of numerical analysis to solve numerous technological problems has been increasingly frequent, owing to its low operational costs. This study aims to simulate an indentation assay with spherical penetrator in systems composed of thin ceramic film deposited on metallic substrate using a Finite Element commercial code. The main objective of this study was to evaluate the field behaviour of stresses in the contact region of the indenter with the sample, on the outline of the impression made by the penetrator and, primarily, on the film-substrate interface.

A demanda por componentes mais resistentes ao desgaste e à corrosão tem promovido um interesse crescente da engenharia de superfícies que desenvolve processos para melhoria das propriedades tribológicas de materiais. O uso de revestimentos cerâmicos tem sido uma opção utilizada para melhorar estas propriedades mecânicas superficiais. Contudo se faz necessário o desenvolvimento de ensaios para avaliação do comportamento mecânico do filme e da sua interface com o substrato, o que requer equipamentos sofisticados, mão de obra especializada, acarretando altos custos operacionais. Com o avanço dos sistemas computacionais, a utilização da análise numérica para solucionar inúmeros problemas tecnológicos tem sido cada vez mais frequente e atualmente permite a sua implementação a baixos custos de processo. Neste trabalho, propõe-se a utilização do Método dos Elementos Finitos, através de um software comercial, para simular o ensaio de indentação com penetradores esféricos em conjugados compostos de substrato metálico e filme cerâmico com diferentes espessuras. Porém a utilização de técnica numérica para avaliar o ensaio de indentação em recobrimentos superficiais finos também tem apresentado desafios, principalmente na obtenção do comportamento mecânico do conjugado. Para melhor representar o ensaio de indentação foram considerados o efeito do coeficiente de atrito entre o penetrador e o recobrimento para, em seguida, serem analisados os campos de tensões e de deformações no conjugado para diferentes profundidades de penetração.Palavras chaves: Ensaio de Dureza, Filmes Finos, Elementos Finitos, Coeficiente de Atrito. ABSTRACTThe demand for components more resistant to wear and corrosion has promoted a growing interest in the surface engineering that develops processes to improve the tribological properties of materials. The use of ceramic coating has been an option used to improve the surface of mechanical properties. However, it is necessary to use tests to evaluate the mechanical behavior of the film and its interface with the substrate, which requires sophisticated equipment, skilled labor and consequently expensive cost. As computer systems have been improving recently, the use of numerical analysis to solve many technological problems has been increasingly frequent and current. Consequently, it allows its implementation with a low cost. This paper proposes to use the Finite Element Method (FEM) to simulate the indentation test with spherical indenters in conjugated compounds of metal substrate and ceramic film with different thicknesses, using commercial software. However, the use of this numerical technique to evaluate the indentation testing also has had problems in obtaining the mechanical properties of the conjugate. In this work, the numerical model also includes the effects of friction between the penetrator and the film to analyze the fields of stresses and strains along the different penetration depths.

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