Mechanical Properties of INCONEL 718 Parts Manufactured by Shaped Metal Deposition (SMD)

Abstract

INCONEL 718 parts have been manufactured by shaped metal deposition (SMD), an additive layer manufacturing technique applying wire-based tungsten inert gas welding. This technique is aimed toward mass customization of parts, omitting time- and scrap-intensive, subtractive fabrication routes. SMD results in dense, “near net-shaped” parts without pores, cracks, or fissures. The microstructure of the SMD parts exhibit large, columnar grains with a fine dendritic microstructure. The interdendritic boundaries are decorated by small Laves phase precipitates and by MC carbides. Tensile tests were performed with different strain rates (10−4, 10−3, and 2 × 10−3 1/s), but no dependency on strength or strain at failure was observed. The ultimate tensile strength was 828 ± 8 MPa, the true plastic strain at failure 28 ± 2%, the micro Vickers hardness 266 ± 21 HV200, and the dynamically measured Young’s module was 154 ± 1 GPa.