Microstructural evolution and mechanical properties of laser-powder bed fusion-fabricated Ti-10Ta-2Nb-2Zr alloy as a potential orthopedic implant material

Titanium alloys are gaining attention for their potential to improve implant performance in biomedical applications. This study investigates the Ti-10Ta-2Nb-2Zr alloy fabricated using laser-powder bed fusion (L-PBF) for potential biomedical applications. The research aims to examine the influence of processing parameters on material structure and properties, and to develop porous structures based on triply periodic minimal surfaces (TPMS) to reduce elastic modulus and improve mechanical compatibility with bone tissue. Spherical Ti-10Ta-2Nb-2Zr powder was processed using L-PBF with varying laser power (250 – 280 W), scanning speed (500 – 1000 mm/s), and hatch spacing (80 – 100 μm). Maximum relative density of 99.91% was achieved at volumetric energy density of 70 J/mm3. Differential scanning calorimetry revealed the β-transus temperature at 862°C. Microstructural analysis showed the formation of martensitic α’-phase in the as-built condition with acicular morphology. Heat treatment at 900°C resulted in the formation of a lamellar α + β structure. Mechanical properties in the as-built condition were characterized by yield strength of 551.8 MPa, ultimate tensile strength of 641.2 MPa, elongation of 19.0%, and elastic modulus of 89.0 GPa. After heat treatment, strength characteristics decreased by 15 – 18%, whereas elastic modulus reduced to 86.0 GPa. TPMS porous structures (gyroid, Schwarz, and split) with 50% porosity demonstrated an elastic modulus of 9.2 – 9.7 GPa, representing approximately 18% of the solid material value. These results demonstrate the potential of Ti-10Ta-2Nb-2Zr as a promising alternative to conventional Ti-6Al-4V for orthopedic applications, offering enhanced mechanical properties and reduced stress shielding due to its lower elastic modulus and tailored porous architectures.