A review of the flow behavior of laser cladding pools based on inclined substrates

The behavior of the molten pool during the laser cladding process significantly influences the formability, microstructure, and mechanical properties of the formed part. Particularly in laser cladding procedures involving inclined substrates, alterations in the gravitational orientation adversely affect the shape and flow dynamics of the molten pool, resulting in a marked reduction in forming precision and overall quality. Consequently, a thorough investigation into the flow dynamics of the molten pool on inclined substrates becomes of paramount importance. We conduct an analysis of the forces acting on the molten pool situated on an inclined substrate. Notably, shifts in gravitational forces induce the molten pool to be deflected in the direction of gravity as well as the humping phenomenon. Appropriately balanced Marangoni forces facilitate efficient heat and mass transfer within the molten pool, while excessive Marangoni forces can trigger destabilization. Viscous and frictional forces serve the purpose of mitigating the adverse impact of gravity by impeding the motion of the molten pool fluid. Gas pressure serves a dual role, restraining the upward growth of the molten pool and upholding its stability throughout the laser cladding process. Notably, the center evaporation effect within the molten pool warrants careful consideration for the reduction of porosity and sputtering. Ultimately, we delve into strategies for controlling the fluid behavior of the molten pool. These strategies encompass unit energy input optimization, nozzle angle adjustments, material composition optimization, and the application of auxiliary external fields. The diverse range of control approaches is synthesized, culminating in an outlook on the potential avenues for steering molten pool flow behavior.