| Resumo : |
Additive manufacturing by binder jetting has emerged as a promising technology to produce complex metal components, with the potential to reduce costs, material waste, and promote scalability. However, challenges related to high porosity limit its application in systems subject to contact fatigue, such as gears. In this context, the objective of this study was to investigate the sequential application of shot peening as a post-processing strategy to optimize surface integrity and improve the fatigue performance of components manufactured by binder jetting. The investigation focused on the detailed characterization of the surface integrity resulting from shot peening applied in two stages: the first dedicated to surface densification and the second to the induction of compressive residual stresses. Parameters such as hardness, porosity, roughness, and residual stress state were evaluated. The first shot peening stage promoted 99% surface density up to a depth of 350?µm, accompanied by a 37% increase in surface hardness and a notable improvement in roughness parameters, establishing a favorable condition for subsequent treatments. The second stage induced compressive residual stresses exceeding -900 MPa at depths of approximately 100?µm, aligned with profiles typically associated with improved fatigue resistance. Rolling contact fatigue tests showed that both treatments significantly extended fatigue life. The combination of densification and stress induction led to an increase of up to 54% in fatigue life compared to the as-built condition. The most significant gains were associated with the suppression of critical surface pores and the stabilization of compressive stress fields. These results indicate that combining densification and residual stress modification strategies is essential to mitigate the intrinsic limitations of binder jetting, promoting improvements in fatigue resistance without compromising part geometry. This study contributes to the advancement of integrated manufacturing routes, combining additive processes and mechanical treatments, with potential application in the production of gears and other critical components, including emerging applications in electromobility, as in sectors such as automotive, as well as in aerospace applications. As a continuation, the validation of these strategies in real geometries under representative operating conditions is proposed. |