AlSi10Mg interlocking structures by Laser Powder Bed Fusion: production and characterization

This thesis work focuses on the design, production and characterization of interlocking structures produced by the Laser Powder Bed Fusion (L-PBF) technique in AlSi10Mg. Interlocking structures represent an engineering innovation that may improve the joining of two different categories of materials, typically a metal and a polymer or polimer matrix composites (PMC), without the use of mechanical joints such as rivets, glues or adhesives. This is made possible by the presence of rows of pins, of different geometry and size depending on the case, placed on the surface of the metal part. Thanks to the mechanical and adhesive bond that is generated between the two materials, it may be possible to obtain high-performance structures, with a significant reduction in accidents due to the formation of cracks within the components, as well as a decrease in design costs. After a careful study of the pin geometries currently existing in the literature, those considered most suitable for the purpose were chosen and, subsequently, produced using two different systems for L-PBF to evaluate which process parameters would lead to better geometric and microstructural accuracy. Therefore, samples were produced to analyze the quality of the Al part, which are divided into microstructure and tomography. Two different L-PBF machines have been used and compared. Some samples have been characterized in the as-built status while a second group was subjected to heat treatment in an oven at 310 °C for one hour. Their microstructural differences were investigated. The samples intended for microstructural analysis underwent a metallographic preparation step to be observed through an optical microscope. In parallel, an observation was carried out at the industrial computerized tomography to perform a three-dimensional reconstruction of the individual pins and porosity analysis. The more promising architectures will be selected for a prosecution of the work where the adhesion of a PMC will be experimented.