Elastic behavior of additively manufactured 316L stainless steel with changing laser power and speed

Abstract

Ultrasonic investigations of additively manufactured 316L stainless steel were performed to reveal correlations between properties and printing parameters. The laser power and scanning speed of the selective-Laser-Melting printing process were varied systematically: 40–100 W in 20-W steps, and 600 mm/s to 1200 mm/s in 200-mm/s steps. Resonant ultrasound spectroscopy and pulse-echo measurements were performed. The extensive data allow for observations of specific behaviors in the elastic properties of the material as a function of VED, the volumetric energy density (VED ∝ power/speed). An increase in the values of c11 and c44 with increasing VED is confirmed, followed by saturation in the expected complete-fusion zone. The saturation values are comparable to those of the wrought (∼250 GPa for c11 and ∼75 GPa for c44). At low VED, c11 is quite small (∼100 GPa). Furthermore, an interesting behavior appears in the incomplete-fusion zone. At a fixed VED, the laser power level affects the elastic properties. As power increases, the porosity decreases, the mass density increases, and both elastic constants increase. The details observed in the material’s elastic properties are important for its correct usage in space and biomechanical applications.