|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Additive Manufacturing for Energy Applications IV
||J-15: Quantifying Equiaxed Versus Epitaxial Solidification in CMSX-4 Single Crystal Superalloy Processed by Laser Powder Bed Fusion Using Single-tracks
||Runbo Jiang, Zhongshu Ren, Joseph Aroh, Amir Mostafaei, Benjamin Gould, Tao Sun, Anthony Rollett
|On-Site Speaker (Planned)
The primary roadblock to successfully print single crystal components using additive manufacturing is the formation of stray grains. In this work, we aim to establish a process window and develop a predictive capability for the propensity of stray grain formation during the fast solidification of single crystal CMSX-4 manufactured by fusion-based additive manufacturing. A systematic study involving solidification modeling and a theoretical analysis of stray grain formation in single crystal welds demonstrated that a reduction of stray grains can be associated with optimal laser processing and rapid epitaxial solidification. This study also utilized advanced high-fidelity computational fluid dynamics simulations coupled with post-mortem microscopy and EBSD to provide guidance for optimizing processing parameters. It showed that, though a higher laser scanning velocity and lower power are generally helpful in the reduction of stray grains, a stable keyhole and minimal fluid velocity further mitigates stray grains in laser single tracks.