Spatial modulation of laser sources for microstructural control of additively manufactured metals

Metal powder-bed fusion additive manufacturing (AM), while demonstrating great potential across a diverse application space, still lacks the necessary control to obtain parts that meet strict performance-driven criteria. In this work, we explore spatial laser modulation to enhance the properties and processability of AM metals. Experiments are carried out with the goals of demonstrating control of the columnar-to-equiaxed transition, identify methods to reduce surface roughness, and extend processing windows for AM alloys. Results show that beam modulation provides site-specific microstructural control, and these results are interpreted using finite element modeling of the melt pool dynamics and thermal profiles.