Laser Additive Manufacturing (LAM) holds the potential to transform the manufacturing sector. However, the fast solidification rates occurring during LAM encourage undesirable effects such as epitaxial grain growth and hot-tearing. These effects are detrimental to the strength, fatigue life and fracture toughness of the printed material. The huge industrial potential of LAM would be further unlocked by tailoring the ‘un-printable’ high-performance engineering alloys for the ultra-fast non-equilibrium solidification process. It is necessary to understand the highly transient mechanisms occurring during rapid solidification. Here, we propose to couple our dedicated in situ and operando DED-LAM system (built with support from the ERC-StG-2020 project GAMMA # 946959) with ID19’s ultra-fast imaging (> 40 kHz) and superior phase contrast to create a unique platform for AM high-performance engineering alloys development to achieve crack-free microstructures.