The demand for high-performance materials in highly corrosive environments has led to growing interest in duplex stainless steels due to their superior mechanical properties and corrosion resistance. Additive manufacturing, particularly Directed Energy Deposition with wire and laser beam, presents a promising method for producing complex duplex stainless steel components. However, imperfections such as porosity, lack of fusion (LOF), and cracks remain critical issues that can significantly affect the mechanical integrity of the manufactured parts.

This study aimed to investigate the types and prevalence of geometrical discontinuities in LMDw-fabricated duplex stainless steel components and to evaluate the influence of line energy on imperfections formation.

Cylindrical parts were fabricated using LMDw with duplex stainless steel wire. Cross-sec-tional samples were prepared, polished, etched, and analyzed using optical microscopy. The defects were quantified using ImageJ software to calculate the area fraction of discontinuities in each sample.

The results showed that imperfection content varied non-linearly with line energy. Low line energy often led to insufficient melting and poor interlayer bonding, resulting in high LOF and porosity. Conversely, excessively high line energy introduced melt pool instability, contributing to moderate defect levels.