Ultrasonic Atomization and 3D Printing of Multiprincipal Equimassic Ti-33Nb-33Zr and Ti-25Nb-25Ta-25Zr alloys for Implant Applications

This work deals with production of spherical ultrasonic atomized powders of multiprincipal equimassic Beta Ti-33Nb-33Zr (TNZ-33) and Ti-25Nb-25Ta-25Zr (TNTZ-25) alloys. The TNZ33 and TNTZ-25 alloys were chosen for its ideal combination of mechanical (low modulus and high strength) and biological properties (corrosion resistance), compared with higher elastic modulus of cp-Ti (E=110 GPa) and Ti-6Al-4V (E=100 GPa). Ultrasonic atomized powders with high sphericity of 0.94 of TNZ-33 and TNTZ-25 alloys were obtained by ultrasonic atomization ATO Lab+ equipment and subsequent 3D printing by laser powder bed fusion of multiprincipal Beta TNZ-33 and TNTZ-25 alloys samples that were printed at laser speeds of 500, 750, and 1000 mm/s (VED of 167, 111 and 83 J/mm3, respectively), for a laser power of 200 W. The results indicate that LPBF samples printed at 500 mm/s exhibited larger grain size for TNZ-33 and TNTZ-25 alloys, characterized by a fine dendritic texture and minimal defects. For 750 and 1000 mm/s speeds grain size decreased due to higher cooling rates imposed by previous substrate printed layers. Microhardness remained constant for TNZ-33 and TNTZ-25 alloys regardless of laser speed (308 - 316 HV and 315 - 323 HV, respectively) and elastic modulus of E=75 and 70 GPa were obtained for TNZ-33 and TNTZ-25 alloys. This study presents new powders produced by advanced ultrasonic atomization method and 3D Printing of multiprincipal equimassic Ti-33Nb-33Zr and Ti-25Nb-25Ta-25Zr alloys with lower elastic modulus suitable for special metallic biomaterials for implant applications. Keywords: β-Ti alloys; multiprincipal alloy, ultrasonic atomization, 3D printing; elastic modulus; mechanical properties; implants.