Advancements in operando X-ray techniques for metal additive manufacturing

Operando X-ray techniques have enabled real-time observation and analysis of metal additive manufacturing (AM) processes, providing invaluable insights into solidification mechanisms and melt pool behavior. In this perspective, we present the current state of the art in X-ray diffraction and imaging studies of laser-based metal AM processes, specifically Directed Energy Deposition and Powder Bed Fusion. We explore various data analyses that can be performed with time-resolved data, including phase identification, microstructural evolution, tracking melt pool behavior, and defect formation. Additionally, we highlight the limitations of existing operando studies and provide an outlook on overcoming these challenges. Additive manufacturing has emerged as a powerful approach for achieving properties that are not possible in conventionally processed alloys. This Perspective provides a state-of-art overview of the use of operando x-ray techniques for understanding solidification dynamics and melt pool behavior in additive processes.