Investigations on Mechanical Properties of Lattice Structures with Different Values of Relative Density Made from 316L by Selective Laser Melting (SLM)

• Published in: Materials Vol. 13; no. 9; p. 2204
• Main Authors: Płatek, Paweł, Sienkiewicz, Judyta, Janiszewski, Jacek, Jiang, Fengchun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 11.05.2020; MDPI
• Subjects: Additive manufacturing; Austenite; Austenitic stainless steels; Crystallography; Density; Design; Diffraction patterns; dynamic compression; Dynamic loads; Dynamic tests; Energy; Energy absorption; Laser beam melting; Laser sintering; lattice structures; Manufacturability; Mechanical properties; Methods; powder bed fusion; Quality control; Rapid prototyping; Residual stress; selective laser melting; Stainless steel; Struts; Titanium alloys; energy absorption; additive manufacturing; dynamic compression; powder bed fusion; selective laser melting; crashworthiness; lattice structures
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma13092204

Nine variants of regular lattice structures with different relative densities have been designed and successfully manufactured. The produced structures have been subjected to geometrical quality control, and the manufacturability of the implemented selective laser melting (SLM) technique has been assessed. It was found that the dimensions of the produced lattice struts differ from those of the designed struts. These deviations depend on the strut orientation in relation to the specimen-building direction. Additionally, the microstructures and phase compositions of the obtained structures were characterized and compared with those of conventionally produced 316L stainless steel. The microstructure analysis and X-ray diffraction (XRD) patterns revealed a single austenite phase in the SLM samples. Both a certain broadening and a displacement of the austenite peaks were observed due to residual stresses and a crystallographic texture induced by the SLM process. Furthermore, the mechanical behavior of the lattice structure material has been defined. It was demonstrated that under both quasi-static and dynamic testing, lattice structures with high relative densities are stretch-dominated, whereas those with low relative densities are bending-dominated. Moreover, the linear dependency between the value of energy absorption and relative density under dynamic loading conditions has been established.