Revealing the Dynamic Changes in Thermal Radiative Behavior during Far-From-Equilibrium Processing in Powder Bed Fusion Additive Manufacturing

Advanced manufacturing is enabling the production of complex metallic components for applications in aerospace, energy, biomedical devices, and national defense. Metal additive manufacturing, in particular, offers unprecedented design freedom but relies on rapid melting and solidification processes that are difficult to monitor and control in real time. A fundamental challenge is accurately measuring temperature during fabrication because the thermal radiation emitted by materials changes dynamically as they undergo rapid phase transformations. Conventional thermal monitoring methods typically assume constant radiative properties, leading to significant errors in temperature measurements and limiting the ability to predict material behavior and manufacturing quality. This award supports fundamental research to establish accurate thermal characterization methods for metal additive manufacturing by revealing the dynamic radiative behavior of materials under far-from-equilibrium conditions. The resulting knowledge will improve process monitoring, enable more reliable manufacturing of high-performance components, and benefit other technologies that rely on high-temperature thermal imaging. The project will also provide interdisciplinary research opportunities for graduate and undergraduate students, strengthen educational activities spanning materials science, mechanical engineering, and manufacturing, and expand outreach programs that engage K–12 students in advanced manufacturing and STEM careers. Accurate thermal monitoring during fusion-based additive manufacturing is hindered by the widespread assumption that material emissivity remains constant throughout processing, despite the rapid changes in temperature, phase, and surface condition experienced during melting and solidification. To overcome this limitation, this research will investigate the transient radiative behavior of metals using an in-situ multi-wavelength pyrometry approach capable of capturing emissivity and temperature simultaneously during fabrication. The project will establish fundamental relationships between dynamic emissivity, thermal history, and energy absorption during rapid phase transformations, while quantifying how these phenomena influence microstructural evolution, defect formation, and process stability. Experimental measurements will be integrated with physics-based modeling to improve the understanding of energy source-material interactions and develop more accurate thermal monitoring methodologies for fusion-based manufacturing processes. The resulting framework will provide new scientific insight into far-from-equilibrium thermal radiation phenomena and establish a foundation for more reliable process control, improved manufacturing quality, and predictive modeling of next-generation metal additive manufacturing systems This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.