Influence of beam shaping via coherent beam combining on the microstructure, texture, and phase composition of super duplex steel in laser-based directed energy deposition (DED-LB/M)

Coherent Beam Combining (CBC) enables near-unlimited variation of spatial laser intensity distributions, offering a novel approach to beam shaping in laser-based directed energy deposition of metals (DED-LB/M). To assess the influence of beam shape on the resulting microstructure and mechanical properties, super duplex steel thin-walled multilayer specimens were fabricated using four distinct beam profiles and comprehensively characterized. The spatial intensity distribution was found to directly govern solidification conditions, grain morphology, crystallographic texture and austenite precipitation behavior. A direct influence of the beam profiles on the geometric key values and specimen quality has been observed as well. Notably, a beam profile with laterally distributed intensity peaks promoted stronger crystallographic texture through variations in the spatially distributed G/R criterion. The results demonstrate that spatial intensity distribution represents an effective parameter for targeted microstructure and property engineering in DED-LB/M.