• Tanguy, Alexandre
• Upadhyay, Manas
• Mohanan, Nikhil
• Slama, Meriem Ben Haj
• Héripré, Eva
• Hallais, Simon
• Gaudez, Steve
• Yedra, Lluis

Abstract

<jats:title>Abstract</jats:title><jats:p>Precipitates in an austenitic stainless steel fabricated via any Additive Manufacturing (AM), or 3D printing, technique have been widely reported to be only Mn-Si-rich oxides. However, via Transmission Electron Microscopy (TEM) studies on a 316L stainless steel, we show that non-oxide precipitates (intermetallics, sulfides, phosphides and carbides) can also form when the steel is fabricated via Laser Metal Deposition (LMD)—a directed energy deposition-type AM technique. An investigation into their origin is conducted with support from precipitation kinetics and finite element heat transfer simulations. It reveals that non-oxide precipitates form during solidification/cooling at temperatures ≥ 0.75T<jats:sub>m</jats:sub> (melting point) and temperature rates ≤ 10<jats:sup>5</jats:sup> K/s, which is the upper end of the maximum rates encountered during LMD but lower than those encountered during Selective Laser Melting (SLM)—a powder-bed type AM technique. Consequently, non-oxide precipitates should form during LMD, as reported in this work, but not during SLM, in consistency with existing literature.</jats:p>

Topics

• Deposition
• impedance spectroscopy
• stainless steel
• simulation
• carbide
• selective laser melting
• transmission electron microscopy
• precipitate
• precipitation
• intermetallic
• directed energy deposition