研究目的

To build a general model to construct the substructure from its two-dimensional morphology and to study the growth direction and crystallographic orientation of the cellular substructure in samples fabricated by laser powder bed fusion.

研究成果

The substructure in SS316L fabricated by LPBF can grow in the form of an oriented array in 3D. A model was built to calculate its growth direction from the 2D morphology, and the three Bunge Euler angles to a unique growth direction were determined. The crystallographic orientation corresponding to the growth direction was obtained. The model was successfully applied to construct the substructure in the single tracks fabricated at different scanning velocities. The transition from cell-like dendrite to the cell was identified by the crystallographic orientation. The critical growth rate of the transition in the single track with power of 200 W was estimated to be around 0.31 ms?1.

研究不足

The study focuses on the substructure in SS316L fabricated by LPBF, and the findings may not be directly applicable to other materials or fabrication methods. The model relies on the quantitative data from the etched 2D morphology, and the unique solution is selected in consideration of the local thermal condition, which may introduce some subjectivity.