Study on the Cracking Behaviour of Nickel-based Superalloys via Laser Powder Bed Fusion
Author of the article: LI Xin1, CHENG Xiang1, HU Pengfei1, LIU Zhuangzhuang1,2
Author's Workplace:1. Key Laboratory for Advanced Materials Processing (MOE), Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China; 2. Beijing Laboratory of Metallic Materials and Processing for Modern Transportation, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
Key Words:nickel-based superalloy; laser powder bed fusion; casting; crackingbehaviour
Abstract:
The research and development of nickel-based superalloys specifically for additive manufacturing involves a
lengthy and costly process of composition design, powder production, printing, and characterization. This significantly
hinders the rapid development and application of new alloys for additive manufacturing. To address this issue, this paper
proposed evaluating the printability of alloy powders by laser scanning ingot materials, thereby avoiding multiple powder
productions during the composition design process. Focusing on four typical nickel-based superalloys (Inconel 718,
Hastelloy X, CM247LC, and Inconel 939), the correlation of cracking in both alloy powders and ingot materials during
laser scanning was investigated. The results indicate that for the low crack sensitivity Inconel 718 alloy, no cracks are
observed in either the laser-scanned powder or the ingot samples. In contrast, the high crack sensitivity alloys CM247LC
and Inconel 939 exhibit solidification cracks in the laser-scanned powder samples due to insufficient interdendritic liquid
phase feeding at the end of solidification under thermal contraction tensile stress and solid-state cracks due to residual stress
during thermal cycling. However, only solidification cracks are found in the laser-scanned ingot samples, indicating that the
types of cracks differ between the two states, but the cracking trends are consistent. For the Hastelloy X alloy, which has
intermediate crack sensitivity, crack-free laser-scanned powder samples can be obtained within a certain process window,
whereas all the parameters used for the laser-scanned ingot samples result in cracks, showing differences in cracking trends
between the two states but with both exhibiting solidification cracks. These findings suggest that analysing the cracking behavior of laser-scanned ingot alloymaterials provides a reference for understanding the cracking behavior of the
correspondingalloypowdersduringlaserpowderbedfusion(L-PBF)formation.