Relatore
Descrizione
Academia and industry have been shown in recent years an increasing interest in lattices realized through additive manufacturing (AM). Such architecture porous structures have a behaviour influence by various factors, including unit cell topology, base material, heat treatments, and relative density. In the present work, an experimental campaign regarding the compressive mechanical behaviour of AM solid-based gyroid lattices made of Ti6Al4V alloy is presented. The work directly investigates the effects of the relative density through specimens characterized by different relative densities values (12.5%, 25%, 37.5%, and 50%); moreover, two sets of specimens per each relative density have been realized to evaluate the effect of two different post-treatment techniques; in particular, the HIP process have been considered to assess if other cheaper solutions may lead to similar beneficial effects on the fatigue properties when dealing with lattices. Micro-CT scans, microstructural, postmortem analysis and finite element analysis are included to better interpret the achieved results. Finally, a comparison with a wider fatigue dataset retrieved from literature is performed in an effort to obtain a more comprehensive understanding of the compressive behaviour of lattices. The results clearly showed that optimized process parameters and cheaper heat treatments ensures beneficial effects similar to those expected by HIP. Furthermore, accuracy and limitations of easy-to-use methodologies to account for the reduction in strength due to the change in relative density presented in literature, such as effective and normalized stress, have been evaluated.
