The Institute of Laser for Postgraduate Studies / University of Baghdad discussed the PhD dissertation submitted by student Samer Nouri Ali, entitled “Laser Direct Energy Deposition of Functionally Graded Stainless Steel 316L – Inconel 625 Alloy” Under the supervision of Assistant Professor Dr. Ziad A. Taha
Laser Directed Energy Deposition (LDED) is considered one of the promising techniques for producing functionally graded materials and advanced metallic structures. However, its performance depends heavily on controlling laser power, scanning speed, and chemical composition. This study aimed to evaluate the simultaneous effect of these variables on the microstructure, deposition quality, and mechanical properties in single, mixed, and functionally graded SS316L–IN625 systems fabricated by LDED technology.
The results showed that laser power, scanning speed, and chemical composition have an integrated effect on melt pool stability, microstructural evolution, defect formation, and mechanical properties. Low heat input increased the likelihood of lack-of-fusion defects and porosity, while high heat input caused coarsening of the solidified microstructure. Increasing scanning speed, when sufficient heat input was available, improved the microstructure and hardness, whereas increasing IN625 content enhanced strengthening mechanisms and the formation of distinctive secondary phases.
The scientific originality of the study lies in identifying an optimal mixed composition and operating conditions that achieved a simultaneous balance between deposition quality and enhanced mechanical properties. The results confirm that precise tuning of chemical composition and process parameters is a critical factor in producing high-density functionally graded materials with superior performance, providing a scientific basis for developing advanced engineered components manufactured by LDED technology.
The dissertation was approved after fulfilling all requirements for obtaining the PhD degree in Laser Applications.
