Numerical analysis on flow and surface topography of the molten pool in laser additive remanufacturing

Laser additive remanufacturing technology is an important technology in the field of manufacturing technology innovation and development, which has largely revolutionized the design and manufacturing mode of high-end devices to a large extent, and is a key component of green remanufacturing that can effectively promote the sustainable and sound development of the manufacturing industry. A multiphase model of laser additive remanufacturing with pulsed lasers is developed to analyze the evolution of the molten pool, the trend of the surface tension for different process parameters, and their relation to the molten pool morphology. The results demonstrate that the maximum flow velocity at the surface of the molten pool is inversely proportional to the pulsed laser frequency and to the duty ratio. While the trend of the height of the cladding layer corresponds to the trend of the heat accumulation in the molten pool, the width and penetration depth of the cladding layer are governed by the size of the heat-affected zone. The cladding layer and substrate will have poor metallurgical bonding if the pulsed laser frequency is too high. When the duty ratio is too large, the likelihood of over-melting increases, affecting the substrate properties and increasing the surface roughness, which is detrimental to the surface finish of the cladding layer.