Rolling contact fatigue test performed on additively manufactured inconel 718 produced by selective laser melting

• Powder bed additive manufacturing (AM) is a method for producing near-net-shape components by selectively melting metal powder where material is desired, layer by later. This is directly contrary to conventional machining being a solely subtractive process where material is removed from a large work piece. It is well known that AM often results in microstructural anisotropy related to the build direction. In the case of Inconel 718, columnar grains are formed, oriented along the build direction. Furthermore, utilizing different scan strategies such as contouring will result in different grain structures in the near surface region compared to the bulk of the material. The aim of this work was to study the effects of these microstructural anisotropies on the mechanical and tribological properties. Cylindrical test specimens with were built with different build directions and scan strategies and mechanically characterized and tested in a rolling contact fatigue test rig where a specimen was placed between two hard rollers. As the very surface presents a rough topography comprised of partly melted powder particles which hinders any tribological function of the component the samples were grinded prior to the rolling contact fatigue tests. After testing, the contact tracks were analyzed using, SEM and EBSD.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Tribologi (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Tribology (hsv//eng)

Nyckelord

additive manufacturing

Inconel 718

rolling contact

fatigue

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