Physical-mechanical behaviors of stainless steel plate-lattice built by material extrusion additive manufacturing

Abstract

Additive manufacturing (AM) technology has been widely adopted for the fabrication of metal lattices due to its freeform design capability over traditional manufacturing methods. However, the prevalent laser-based AM technologies possess high energy and investment consumption, and relatively low manufacturing speed, hampering their widespread adoption in building metal lattice components. In this study, an integrated approach of material extrusion AM, debinding, and sintering was introduced to produce 17–4 PH stainless steel plate-lattice structures in a time-efficient and cost-effective way. Three types of plate-lattice structures, namely body-centered cubic (BCC), face-centered cubic (FCC) and their combination (BCC-FCC), were successfully fabricated. Physical-mechanical behaviors, including physical deformation and compressive properties, were investigated through modeling, simulation, and experiments. Specifically, the shrinkage of the final sintered parts was predicted by the analytical modeling and characterized by experimental observation, the results of which showed a good consistency. The plate-lattice structure exhibited equiaxed grains on each surface, with a small portion of lath martensite observed at the top surface. Numerical simulation and compression test were conducted to reveal the compressive modulus, yield strength, and the fractural response at large compressive strains. All three types of plate-lattices possessed a lower compressive modulus than the simulated value, but still exhibited extraordinary yield strength under the compressive force compared to the truss-based or triply periodic minimal surface lattices. The successfully built metal plate-lattice structure verifies the great potential of material extrusion AM process, showing a great promise to fabricate complex metal lattice for large scale applications.