Microstructure and wear characteristics of austenitic stainless steel coatings fabricated through various directed energy deposition

Austenitic stainless steels are widely used in automotive and marine environments because of their high toughness, corrosion resistance, and wear resistance. The present comparative study focuses on the microstructure and wear resistance of double-layer austenitic stainless-steel coatings prepared on a ductile iron substrate using circular spot high-speed laser-directed energy deposition (DED) and broad-beam laser-DED. The results indicate that while the deposition process does not alter the physical phase of coating, it does influence the preferred orientation of surface grains. Both coatings exhibit characteristics of hypoeutectic alloys, where the harder eutectic structure serves as a skeleton to resist external pressure. The high-speed laser-DED coating demonstrates higher hardness and wears resistance due to its denser eutectic structure. In addition, its finer microstructure produces smaller wear debris, contributing to the formation of a denser oxide film, thereby enhancing wear resistance.