Extreme gradient boosting-based multiscale heat source modeling for analysis of solid-state phase transformation in additive manufacturing of Ti-6Al-4V

The formation of the microstructure throughout the manufacturing process in metal additive manufacturing (MAM) significantly affects the properties and functionality of the resulting component. Hence, gaining a comprehensive understanding of microstructure development is crucial to predict and control the fabricated part's performance effectively. Since the temperature difference significantly impacts microstructure evolution, it is important to get a precise temperature history during the MAM process. However, evaluating the temperature history demands considerable computational resources, particularly for a part-scale analysis. Therefore, this paper presents a part-scale heat source model that enables analysis on a larger scale without losing consistency with a microscale moving heat source model. In particular, this paper proposes a multi-stage calibration framework that bridges empirical experiments with multi-scale heat source models. Finally, the calibrated part-scale heat source model was utilized to examine the solid-state phase transformation (SSPT) occurring in different structures' MAM processes. Then, the effect of heating cycles on the formation of microstructures throughout the multi-track and multi-layer MAM process was examined. Subsequently, the proposed methodology enables the analysis of microstructure transformation at part-scale with affordable computational cost. It facilitates understanding the interplay between process and part geometries in the additive manufacturing of metallic components in terms of SSPT. In other words, our framework guides the process's design by linking the part-scale geometries and the microstructure transformation.