A second-generation apparatus for in situ synchrotron characterisation of directed energy deposition additive manufacturing with multi-modal monitoring and external forces

• BAMPR-II enables high resolution multi-modal in situ monitoring of DED-AM. • BAMPR-II replicates a wide range of industrial conditions in both laser processing parameters and environmental parameters. • Simultaneous multi-modal imaging across a range of different sensors enables correlation of process-structure–property relationships in situ and in operando and calibration of non-synchrotron-based techniques. • The application of external fields, such as thermal, magnetic, or ultrasonic, allows for the investigation of fundamental phenomena from these field interactions. In situ synchrotron studies of Directed Energy Deposition (DED) additive manufacturing provide unique process insights, using high-resolution spatial and temporal observations to reveal melt pool dynamics, phase evolution, and defect formation mechanisms. However, capturing these phenomena under industrially relevant conditions remains a challenge. Here, a second-generation DED apparatus is presented that replicates industrially relevant process conditions whilst enabling multi-modal in situ monitoring, including synchrotron X-ray radiography and diffraction, infrared (IR) imaging, inline coherent imaging (ICI), and optical imaging. The equipment, termed the Blown-powder Additive Manufacturing Process Replicator-II (BAMPR-II), also facilitates a range of unique process adaptations including the application of heat, magnetic fields, and ultrasound. Two case studies are described demonstrating how BAMPR-II reveals the underlying phenomena controlling DED, including: (1) simultaneous X-ray and ICI imaging to capture cracking mechanisms during DED; and (2) X-ray imaging of DED illustrating how magnetic fields can control flow in the melt pool.