Laser Powder Bed Fusion (LPBF) process holds significant potential in material design and offers the ability to engineer locally microstructures. However, alloys produced via LPBF often exhibit distinct microstructure features compared to traditional casting methods, primarily attributed to the directional temperature gradient and rapid cooling rate inherent in the LPBF process. This heterogeneity in microstructure further leads to the difference in mechanical properties. In this study, we developed a physics-driven framework on process-structure-property relationships for a LPBFed scandium-modified alloy. A Cellular Automaton (CA) model is implemented for the investigation of the microstructure evolution and a physics-based crystal plasticity (CP) model is used for predicting the mechanical properties. For modelling the precipitation of second phases during the melt, a Classical Nucleation and Growth (CNGT) model has been coupled with the CA model to determine the volume percentage and average size of the major Al3Sc precipitates during printing. This microstructure, compared with characterization, is validated and applied as a representative volume element (RVE) in CP model simulations. For validation, the simulation results are compared with experimental findings.