Fatigue and Fracture Behavior in Advanced Layer-Level SS316L-17-4PH Multi-Material Fabrication via Powder Bed Fusion—Laser Beam

The advent of AM engendered unprecedented control over materials distribution, spurring interest in multi-material fabrication. Among AM techniques, powder bed fusion—laser beam (PBF-LB) stands out, although it requires adaptation for multi-material printing. Several prototypes have been developed, aiming to preserve the cost-effectiveness of PBF-LB to encourage industrial uptake and scalability. However, ensuring component reliability remains critical, as defects at material interfaces can compromise performance. Notably, literature suggests that a judicious combination of soft and hard materials may enhance the fatigue properties via shielding effects. This study investigates the fatigue behavior of multi-material components made of 17-4PH and SS316L, produced via the intralayer multi-material PBF-LB process. It examines as-built and mirror-polished conditions through microstructural, chemical, and failure analysis to explore the observed fatigue behavior. Results show reliable bonding with failures at the weaker material, SS316L. Surface condition influences crack initiation and propagation, highlighting its importance in multi-material AM design.