Tribological and mechanical behavior of AISI 316L lattice-supported structures produced by laser powder bed fusion

Combining the geometrical freedom provided by laser powder bed fusion (L-PBF), a powder bed fusion additive manufacturing (AM) process, and tailoring the mechanical properties by the use of lattice structures, many applications benefit from lightweight lattice structures such as aerospace and biomedical. Many different aspects of the lattice structures produced by L-PBF have been addressed in the literature including weight reduction, energy damping, compression behavior, manufacturability, and surface characteristics. Although lattices are seen as a promising design tool, the influence of using lattices inside the part surface on the wear behavior of L-PBF specimens has not yet been addressed in the literature. In this study, the effect of different lattice structures varying in unit cell geometry and size, built along different directions on the wear behavior, is addressed using AISI 316L powder processed with L-PBF. Moreover, to understand the wear behavior in detail, microhardness and compression testing of the samples were accomplished. As a result, it is found that the microhardness measurements change by only 5% on different build directions, whereas the lattice type is a significant factor regarding the modulus of elasticity and absorbed energy per unit volume. Moreover, it is concluded that although the coefficient of friction has an average value of 0.7, it does not vary depending on the tested factors, whereas the specific wear rate is influenced by the build direction and part geometry. Thus, for applications where tribological properties are important, the effect of heat dissipation and cooling rate leading to microstructural changes needs to be considered when utilizing L-PBF.