Manufacturability and Bending Performance of Graded Steel Structures Fabricated by Selective Laser Melting

Abstract

The objective of this research work is to investigate the processing, structure, properties, and performance of stiffness/hardness-graded stainless steel 316L bulk samples fabricated via selective laser melting (SLM) additive manufacturing. By systematically altering the location-specific volumetric energy density imparted (via process-parameter change), variations in microstructure and density can be achieved; these result in intended changes to mechanical properties such as moduli, hardness, etc. Based on a design of experiments, ASTM-standard samples that have mechanical property gradations as a function of the distance from the neutral axis were fabricated to evaluate performance when subjected to standard bending tests. Digital image correlation (DIC) was employed to capture local and global deformation. Further, the characteristics of each of the zones, as well as interfaces between zones were investigated via microscopy and indentation testing. Altogether, this study is expected to provide insights into the additive manufacturability of such spatially tailored structures, their resulting property distributions, and their performance in various engineering applications.