Comparison of mechanical properties of lattice structures produced by EB-PBF and LB-PBF methods

Additive manufacturing, taking more and more place in our lives due to the flexibility provided to the sector in terms of design and supply. In aviation industry, AM has gained momentum, as it enables weight reduction, consolidation and enables complex structures to be produced. Topology optimization and the lattice structures are the leaders of the weight reduction. Lattices are a type of cellular materials with lattice-like frameworks that can be optimized for specific loading conditions. In the thesis, strut and TPMS type lattices were selected. As an example of both lattice types, BCC and Gyroid were preferred. The tensile and compressive behavior of BCC and Gyroid type lattice structures with different cellular fill rates and cell sizes were compared for Titanium alloy in both LB-PBF and EB-PBF. In both AM methods, sample designs were made for tensile and compression tests, the production of the samples were determined, the secondary processes were applied and the tests were carried out. After examining the tensile tests, mechanical properties were improved with increasing cellular fill rates in both lattices, but Gyroid ones had higher tensile and yield strengths in samples with the same cell size and occupancy rate. In the case that the lattice type and cellular fill rates do not change, tensile and yield strengths of the samples with lower cell-size were higher in both AM methods. When the compression test results were examined, it was observed that the energy absorption and the initial maximum stress values increased with increasing cellular fill rates.