Tensile performance and plastic anisotropy of material extrusion steel 316L: influence of primary manufacturing parameters

Material extrusion (ME) offers a low-cost alternative to other metal additive manufacturing (AM) methods, gaining, in effect, considerable attention from the AM community. However, there is still a paucity of research on the mechanical performance of the material produced with a variety of ME manufacturing parameters. This paper presents an experimental study on the tensile performance and plastic anisotropy of ME Ultrafuse Steel 316 L. Mechanical testing under quasi-static tensile loading conditions has been conducted on specimens produced with a variety of ME manufacturing parameters. The effect of primary manufacturing parameters, namely layer height, print speed, and raster angle, on the elastoplastic behaviour of this material has been examined. Analysis of variance (ANOVA) on the mechanical testing results has been used to investigate the relationship between these manufacturing parameters and the resulting mechanical properties. The failure mechanisms of the specimens were examined, with digital image correlation (DIC) employed to map local strain fields during plastic deformation. The experimental results confirm the existence of non-uniform transverse straining and the variation of plastic anisotropy between two raster angles ( ± 45° and 0°/90°). The ± 45° raster angle specimens outperformed their 0°/90° counterparts, while the former have also exhibited a more ductile behaviour when compared to the latter. The visual representations of the strain evolution in the specimens during deformation confirmed the existence of a non-uniform deformation, even at low tensile strain, owing to the different ME manufacturing parameters. Overall, it has been found in this study that the print speed does not have substantial influence on the tensile performance of the material, while, on the other hand, the raster angle and the layer height appear to have a significant influence.