The effect of laser beam profile on the melt pool shape and dendrite growth orientation during the melting and solidification of a single-crystal alloy

Single-crystal (SX) superalloys are critical for aerospace applications due to their excellent high-temperature strength and creep resistance. Laser additive manufacturing offers a promising route for fabricating SX alloys; however, controlling crystallographic growth remains challenging due to complex thermal conditions. Beyond conventional laser parameters, the laser beam intensity profile plays a key role in governing melt pool geometry and dendrite growth. This study numerically investigates the influence of different laser beam intensity profiles on solidification behaviour and dendrite growth direction in laser-melted CMSX-4 single-crystal nickel-based superalloy. Gaussian, annular ring, and their combined beam distributions are analyzed to identify optimal conditions for promoting grain growth along preferred crystallographic directions. The results provide guidance for tailoring laser beam profiles to control crystal growth and microstructure during laser processing of single-crystal superalloy surfaces.