|About this Abstract
||MS&T21: Materials Science & Technology
||Additive Manufacturing Modeling and Simulation: Microstructure, Mechanics, and Process
||Mitigating Stray Grain Nucleation during the Laser Powder Bed Fusion of Single Crystal CMSX-4
||Runbo Jiang, Zhongshu Ren, Tao Sun, Anthony Rollett
|On-Site Speaker (Planned)
Even though the as-built microstructure of Laser Powder Bed Fusion parts is dominated by epitaxial grain growth continuing across the individual layers, stray grains frequently occur in laser melting of single crystals. The presence of these stray grains inserts grain boundaries and degrades high temperature properties. Within the current work, laser processing parameters were varied and stray grains were characterized within individual melt tracks in single crystal CMSX-4. Solidification and fluid flow modeling was performed using Flow-3D Computational Fluid Dynamics (CFD) to predict locations where nucleation has the highest probability to occur in the melt pool. Electron backscatter diffraction (EBSD) mapping was used to calibrate the CFD simulation and provides important information on stray grain area fraction and spatial distribution in the melt pool. It was found that compact melt pools with nearly semi-circular cross-sections are the least likely to exhibit stray grains.