About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
Additive Manufacturing: Design, Materials, Manufacturing, Challenges and Applications
|
| Presentation Title |
Evolution of Solidification Microstructure in Laser Powder Bed Fusion: Role of Epitaxy, Growth Direction, and Thermal Gradients |
| Author(s) |
Prosenjit Biswas, Zhongshu Ren, Tao Sun, Ji Ma |
| On-Site Speaker (Planned) |
Prosenjit Biswas |
| Abstract Scope |
In laser powder bed fusion (LPBF), the growth direction of cellular dendrites within the melt pool is determined through competition among epitaxial growth, preferred growth directions, and maximum thermal gradients (Gmax). However, the dominant factor and the specific role of each in developing melt pool microstructures remain unclear. In this study, we performed single laser track scans on SS316L single crystal substrate and combined experimental characterization of microstructure growth directions with Computational-Fluid-Dynamics simulations of thermal gradients to determine each factor’s contribution. Our results reveal that epitaxial growth dominates microstructure development by preferentially growing along one of the {100} directions of grains adjacent to the melt pool boundary, without cellular bending or secondary-arm formation. The selection of this {100} growth direction is governed by the local thermal gradient magnitude at the solid-liquid interface, instead of Gmax. These findings offer valuable insights for achieving precise control over microstructure evolution in LPBF components. |