Enhanced Bending Performance through Variable Lattice Density in DMLS-Fabricated 17-4 PH Stainless Steel Hybrid Structures

Metal additive manufacturing has advanced significantly with materials like titanium, stainless steel, and aluminum alloys, yet the relationship between lattice density and mechanical performance remains insufficiently understood for hybrid structural applications. This study investigates how variable lattice density influences mechanical properties in bending mode for metal 3D printed 17-4 PH Stainless Steel components. We fabricated bending test specimens with hollow cores using Direct Metal Laser Sintering (DMLS): some with systematically varied ultrafine lattice structures and others left empty, all maintaining identical external geometry. All specimens underwent ASTM E290 four-point bending tests, with results validated against finite element analysis models to quantify structural behavior. Our findings revealed that ultrafine lattice structures significantly enhanced effective stiffness and bending strength compared to hollow specimens, with only a relatively small increase in mass (4-26%), exhibiting substantial improvement in bending stiffness. Experimental results correlated strongly with FEA predictions, validating our computational models for future design optimization. These results provide quantifiable relationships between lattice density and mechanical performance, enabling advanced applications across multiple industries with improved bending stiffness and minimal mass addition.