Preparation and Post-Processing of Three-Dimensional Printed Porous Titanium Alloys

Ti6Al4V is widely utilized in orthopedic implants due to its excellent mechanical properties, corrosion resistance, and biocompatibility. However, traditional solid titanium implants exhibit an elastic modulus (90-115 GPa) significantly higher than that of human bone (10-30 GPa), leading to stress shielding and implant loosening. To address this, porous titanium alloys have been developed to better match bone elasticity. Additive manufacturing, particularly selective laser melting (SLM), enables precise control over pore size and porosity, thereby tuning mechanical properties. Nevertheless, SLM-produced porous structures often suffer from powder adhesion, which compromises bone integration and patient safety. In this study, bulk Ti6Al4V samples were fabricated via SLM with a fixed laser power of 200 W and varying scanning speeds (800-1400 mm/s). Density measurements and surface defect analysis identified 1200 mm/s as the optimal scanning speed. Cubic unit cell scaffolds with different pore diameters (400, 600, 800 μm) and porosities (60%, 80%) were subsequently designed. Compression tests revealed that scaffolds with a 400 μm pore diameter and 60% porosity exhibited the highest compressive strength (794 MPa) and fracture strain (41.35%). Chemical polishing using a diluted HF-HNO₃ solution (1:2:97) effectively removed adhered powder without significant structural degradation, with 40 min identified as the optimal polishing duration.