Machining influence on the fatigue resistance of Inconel 718 fabricated by Selective Laser Melting (SLM)

Autor: René Leroy, Hicham Chibane, S. Periane, Antoine Morandeau, Sébastien Vaudreuil, Arnaud Duchosal, J. Cormier
Rok vydání: 2019
Předmět:
Zdroj: Procedia Structural Integrity. 19:415-422
ISSN: 2452-3216
DOI: 10.1016/j.prostr.2019.12.045
Popis: Selective laser melting (SLM) is one of the most used additive manufacturing processes, using which complex parts can be built with high dimensional accuracy in a flexible manner with less material usage. The aerospace industry relies on SLM technique to manufacture components like turbine and compressor blades which has a high demand in its dimensional tolerance. Inconel 718 which is a nickel based super alloy used in steam turbine, jet engines where it is subjected to high thermomechanical loads. Inconel 718 is the most preferred alloy in the above applications due to its highest strength-to-weight ratio, its excellent resistance to fatigue, creep and corrosion. Inconel 718 is mainly strengthened by the precipitates which were formed during the heat treatment process by the combination of elements like Nb, Ti and Al along with the base element Ni. In this paper microstructure analysis of as-built and heat treated samples were done along with the evaluation of its mechanical characterization. Followed by the machining test under dry and emulsion conditions using the same cutting parameters. The surface integrity evaluation were done before performing four point bending fatigue test. The fatigue fracture of the sample corresponding to number cycles to failure along with the fractographic analysis of the dry and emulsion machined samples was investigated. The fatigue crack failure is compared to each process of machining to determine the best machining condition for Inconel 718. The best machining condition is dry compared to emulsion as it gives better surface roughness, more compressive residual stress due to which dry machined samples sustained more cycles to failure.
Databáze: OpenAIRE