Unravelling the origin of multiple cracking in an additively manufactured Haynes 230

Abstract

ABSTRACTIn this work, by using multi-scale characterizations from electron channeling contrast imaging (ECCI) to atom probe tomography (APT), we directly evidenced that the massive cracking events in the selective-laser-melted (SLMed) Haynes 230 superalloy are due to the continuous decoration of an M23C6-type thin film at grain boundaries. The high-melting-point nature of the carbide rules out the possibility of liquidation cracking, while the long and straight film surface facilitates stress-induced solid-state cracking. Impurities, Si, Mn and Fe, greatly enhance the cracking susceptibility despite the interesting fact that they are strongly depleted from the carbide.

Keywords

• Ni-based superalloy
• additive manufacturing
• cracking
• elemental segregation
• atom probe tomography