Unravelling the origin of multiple cracking in an additively manufactured Haynes 230
Junyang He, Rui Wang, Na Li, Zhongrun Xiao, Ji Gu, Hongyao Yu, Zhongnan Bi, Weihong Liu, Min Song
Abstract
In 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.