This study investigates the significance of surface characteristics of aluminum alloys in resistance spot welding (RSW), focusing on how these properties influence various welding parameters and the resulting weld quality. Additionally, artificial intelligence (AI) is used to analyze the influence of the material's surface properties on joinability and to predict the joining results.

First, the oxide and passivation layers are examined. The growth rate of the oxide layer is crucial, as it affects the electrical contact resistance during welding. Previous studies have shown that a thicker passivation layer increases contact resistance, potentially degrading weld quality. Various methods for characterizing the oxide layer thickness are evaluated, including X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM), which offer resolutions in the nanometer range.

The study extends to an investigation of surface topography, which is shaped by the rolling process and sheet texturing. The distribution of chemical elements near the surface is compared to that at the core of the aluminum sheet, influenced by solidification behavior and resulting differences in chemical composition.

Another significant aspect of the investigation is the analysis of lubricants on the surface from previous forming processes. Due to limitations of techniques such as TEM and XPS, this study explores, evaluates, and applies the most suitable methods for quantifying the amount of lubricant. The behavior of lubricants on uneven surfaces and their interaction with adhesives and passivation layers is particularly analyzed.

Additionally, the effect of storage time after passivation on the welding process is evaluated, considering how prolonged storage might alter surface properties and impact weld quality. To enhance the predictive accuracy of these analyses, AI and machine learning techniques are integrated, enabling automated interpretation of complex data sets.

This research contributes to a better understanding of the mechanisms and influences of surface characteristics on resistance spot welding of aluminum alloys. The findings aim to provide a foundation for future work and potential optimizations in welding technology.