Process-related tribological and corrosion behavior of additively manufactured 17-4 PH stainless steel

The present experimental study investigated the tribological behavior of 17-4 PH stainless steel produced by three different additive manufacturing (AM) processes: laser powder bed fusion (LPBF), atomic diffusion additive manufacturing (ADAM), and metal extrusion additive manufacturing (MEAM), compared to a conventionally manufactured reference. Samples were tested with untreated and polished surfaces under unlubricated, i.e. technically dry, and oil-lubricated sliding conditions with mixed and boundary friction. A statistical surface analysis using ISO 25178 parameters and a principal component analysis enabled a quantitative comparison of AM-specific topographies. Furthermore, microstructure, chemical composition, mechanical properties, friction, wear behavior, and corrosion resistance were comprehensively analyzed. Results showed that surface morphology and porosity strongly influence friction and wear, often more than hardness. Under unlubricated conditions, ADAM exhibited high friction and wear due to sharp surface peaks, despite its high hardness. MEAM showed low friction, likely due to lubricating effects from residual binder. In contrast, in oil-lubricated conditions, ADAM demonstrated negligible wear and the lowest friction, benefiting from its fine porous surface. LPBF achieved high density and wear resistance but showed the lowest corrosion pitting resistance due to larger surface defects. The study emphasizes that tribological performance in AM components is strongly process-dependent and must be assessed holistically. The presented methodology provides a framework for selecting and optimizing AM processes for components that are also subjected to tribological and possibly corrosive influences.