Characterization of Cold-Sprayed Aluminum-Stainless Steel Dissimilar Laser Welds and Deep Learning-Based Weld Penetration Classification

Laser welding offers advantages like high speed, narrow seams, and reduced heat-affected zones, but is limited when joining dissimilar materials such as aluminum (Al) and low-carbon steel (Fe) due to differences in physical properties and the formation of brittle intermetallic compounds (IMCs), including FeAl 2 and Fe 2 Al 5 . To address this, cold spray technology propels Fe powder at high velocity to create mechanical bonding, suppress IMC formation, and enhance interface stability. In this study, laser welding was applied to overlapped joints of stainless steel, a cold-sprayed Fe layer, and aluminum. Mechanical and microstructural properties were evaluated under varying welding parameters and corrosive environments. Additionally, a CNN-based model using thermal and molten pool images from CMOS and IR cameras was developed to classify weld penetration states. The findings confirm cold spray’s effectiveness as an interlayer method and show that AI enables process control over weld penetration.