Mechanical Performance of Additively Manufactured Diamond Metal Lattice Structures

Abstract

Additive manufacturing has the potential to fabricate intricately designed structures that newlineare conventionally impossible to produce. Among them, selective laser melting (SLM), newlinestereolithography (SLA), and direct metal laser sintering (DMLS) are a few exemplary newlinetechniques for fabricating intricate porous structures for lightweight applications. newlinePorous structures are often lightweight and follow either ordered or random repetitive newlinepatterns, called representative volume elements (RVEs). Ordered repetitive structures newlineare inspired by crystalline lattice structures. These ordered porous metallic structures newlineare called metal lattice structures (MLSs). MLSs are preferable because of their newlinepredictable mechanical performance, as opposed to the anisotropic performance newlineexhibited by randomly distributed porous structures. newlineMLSs are classified on the basis of their crystal structure as simple cubic (SC), bodycentred newlinecubic (BCC), face-centred cubic (FCC), hexagonal close-packed (HCP), newlinediamond, and fluorite-based MLSs. In crystallography, diamond unit cells (RVEs) have newlineone of the lowest atomic packing factors (APF) of 0.34; this low APF is preferable for newlinebuilding lightweight MLSs, on the basis of diamond RVEs for the present work. newlineThis thesis investigates diamond MLSs fabricated via the SLM technique and newlinedeveloped three design strategies to improve mechanical performance by reducing the newlinestress concentration at the strut juncture: (i) node-reinforcement in SS316L, (ii) newlinealuminium-6061 infiltration of SS316L lattices, and (iii) a novel node-compensation newlinetechnique in Ti6Al4V. newlineDiamond MLSs with plain cylindrical struts have been reported to possess high yield newlinestrength and energy absorption properties. Node-reinforced diamond RVEs were newlinedesigned and linearly patterned to form lattices in SolidWorks 2022. A 3x3 full-factorial newlinedesign was used to vary the strut diameter (300and#956;m, 350and#956;m, 400 and#956;m) and node diameter newline(425 and#956;m, 525 and#956;m, 625 and#956;m). Quasi-static compression followed ISO 13314, and both newlinethe diamond lattice structure (DLS).