Influence of Ball Burnishing Path Strategy on Surface Integrity and Performance of Laser-Cladded Inconel 718 Alloys

This study investigates the influence of ball burnishing (BB) path strategies on the surface integrity and functional performance of laser-cladded Inconel 718. Three BB strategies—(1) BB-Longitudinal, (2) BB-Transverse, and (3) BB-Crosshatch—relative to the laser scan trajectory were evaluated and compared against ground surfaces as a baseline. Post-processing BB treatment were demonstrated to be effective in modifying the subsurface layer of the cladded Inconel 718 material, extending to depths of up to 100 µm, increasing dislocation density by over 2.5 times, and enhancing hardness from 260 HV5 (ground) to as high as 461 HV5. These microstructural improvements led to significant gains in corrosion and impact resistance, despite a rise in surface roughness from Ra 0.35 µm (ground) to up to 2.38 µm for BB-Longitudinal surfaces. Impact testing revealed up to 35% reduction in indentation volume, particularly with BB-Transverse and BB-Crosshatch strategies. Nonetheless, sliding wear tests did not confirm improvements in wear resistance, as wear depths exceeded the hardened layer and abrasive wear remained dominant. Electrochemical testing in 3.5 wt.% NaCl solution showed a positive shift in corrosion potential (Ecorr) exceeding 200 mV compared to the ground condition, indicating reduced corrosion susceptibility for BB-Longitudinal condition. Among the tested strategies, BB-Transverse offered the most balanced enhancements, highlighting the complex interplay between laser cladding heterogeneities and post-processing response in optimizing surface and mechanical properties of Inconel 718 claddings.