Mechanical behavior of macroscopic interfaces for 3D printed multi-material samples made of dissimilar materials

The development of 3D printing technologies has introduced new possibilities in producing multi-material parts, and Fused Filament Fabrication (FFF) is one of these technologies. Typically, multi-material parts are made of different blends of the same material, also known as multi-color 3D printing, or from materials with good chemical compatibility. Conventionally, a simple face-to-face bonding interface between part components and chemical bonding between thermoplastics define the mechanical performance of multi-material components. In this regard, the paper aimed to investigate the contact interface strength of multi-material specimens using a geometric approach. Therefore, several geometrical interfaces, such as dovetail, omega, T-shape, and others, were used to interlock pars of low-compatibility thermoplastic polymers, styrene-acrylonitrile acrylic (ASA), and thermoplastic polyurethane (TPU). In the case of one of these interfaces, modeling by the finite element method was resorted to obtain additional information regarding the processes that develop at the interface level between the two components of the joint during the tensile loading. The results showed that the macroscopic interlocking interfaces significantly improved the mechanical properties of the multi-material specimens.