Investigation on Morphology and Mechanical Properties of Rod Units in Lattice Structures Fabricated by Selective Laser Melting

Abstract

Selective laser melting (SLM) fabrication of lattice structures has attracted considerable interest due to its many immanent advantages, such as high specific strength. A wide variety of lattice structures have been designed and fabricated. However, as a vital prerequisite for design optimization, a clear relation between the process constraint of SLM and the apparent properties of the fabricated lattice structure has received much less attention. Therefore, this work systematically investigates the characterization and preformation of rod units, which are the basic components of lattice structures, so as to evaluate the SLM manufacturability of lattice structures. A series of rod units with different inclination angles and diameters were fabricated by SLM. Their morphology and mechanical properties were measured by scanning electron microscope observation and a tensile test, respectively. The inclination angle was found to have significant effects on profile error and little effect on mechanical properties. The higher the inclination angle, the larger the profile error. The characteristic diameter had no significant correlation with profile errors and mechanical properties. Based on systematic studies, a formula is proposed to evaluate the cross-sectional area of the fabricated rod units and further estimate their load capacity. This has important implications for optimizing the design of lattice structures fabricated by SLM.

Structure, Martensitic Transformation, and Damping Properties of Functionally Graded NiTi Shape Memory Alloys Fabricated by Laser Powder Bed Fusion

“…Recently, the fabrication of NiTi SMAs by additive manufacturing (AM) has been frequently addressed [ 26 , 27 , 28 , 29 , 30 , 31 ], due to its ability to fabricate geometrically complex NiTi structures, which are quite challenging to fabricate via conventional approaches (e.g., casting, machining). Among the AM technologies, laser powder bed fusion (L-PBF) has attracted much attention [ 32 , 33 , 34 , 35 , 36 , 37 ] due to the fact that L-PBF fabricated parts normally have a higher dimensional accuracy and better surface finish. Moreover, L-PBF also shows a great potential to act as a metallurgical method to modify the microstructure and phase transformation temperatures of NiTi alloys.…”

Design of Hierarchical Architected Lattices for Enhanced Energy Absorption

“…Al-Saedi et al demonstrated improvements in mechanical properties and energy absorption efficiency over a wide range of loads when introducing a density gradation in lattices [ 15 ]. Tancogne-Dejean et al studied metallic microlattice materials and demonstrated high specific energy absorption under static and dynamic loading [ 16 ]. Spear and Palazotto presented statistical modeling and studied the effect of lattice topology, cell size, cell density, and surface thickness on the mechanical properties of lattice structures.…”