Abstract

Inconel 52M is increasingly utilized in the nuclear and energy sectors for components requiring superior resistance to stress corrosion cracking and extreme environmental degradation. Laser cladding with Inconel 52M wire offers a cost-effective solution for coating low alloy steels; however, achieving optimal corrosion performance remains a challenge due to the sensitivity of the process to deposition parameters. This study investigates the critical influence of processing parameters (specifically travel speed, wire feed speed, and laser power) on the deposition mode and resulting melt pool geometry, and their subsequent impact on microstructural morphology and corrosion resistance. Experimental results demonstrate that the geometry of the melt pool is a governing factor in the corrosion performance of the clad. Contrary to the conventional understanding that substrate dilution is the primary driver of reduced corrosion resistance, this work establishes that the formation and growth of coarse Al- and Ti-oxides are the dominant deleterious factors. High-speed imaging and microstructural analysis revealed that a larger melt pool size promotes the coalescence of these coarse oxides, which disrupt the passive film and serve as initiation sites for pitting corrosion. Conversely, processing parameters optimized to maintain a small melt pool restrict oxide growth, resulting in a dispersion of micro- and nano-sized secondary phases. This morphology facilitates the formation of a stable, compact passive oxide film, significantly enhancing corrosion resistance. These findings provide a pathway for manufacturing high-performance coatings tailored for extreme conditions by strictly controlling melt pool dynamics.