Laser-deposited Ti-Nb-Zr-Ta orthopedic alloys.
The complex quaternary Ti-35Nb-7Zr-5Ta orthopedic alloy has been successfully deposited from a powder feedstock consisting of a blend of elemental titanium, niobium, zirconium, and tantalum powders, using the laser engineered net-shaping (LENStrade mark) process. In the as laser-deposited form, these alloys exhibit a substantially higher tensile strength as compared with more conventionally processed counterparts of similar composition, while maintaining excellent ductility and a low modulus. Furthermore, the as-deposited alloys appear to exhibit a <001> texture, with a substantially large number of grains of the beta phase aligning one of their <001> axes nearly normal to the substrate or parallel to the growth direction. The microstructure of the as-deposited as well as tensile-tested alloys have been characterized in detail using scanning electron microscopy (SEM), orientation microscopy (OM), and transmission electron microscopy (TEM). Formation of a high density of shear bands, possibly arising from slip localization due to precipitates of the omega phase in the beta matrix, is clearly evident in the tensile-tested sample. The enhanced tensile strength and low modulus in these laser-deposited alloys coupled with the ability to form near-net shape components makes LENS an attractive processing technology for orthopedic implants.
Banerjee
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Department of Materials Science and Engineering, University of North Texas, Denton, USA. banerjee@unt.edu
Nag
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Samuel
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Fraser
H L
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D000497:Alloys / Q000737:chemistry*; D007834:Lasers; D008854:Microscopy, Electron; D009556:Niobium; D013635:Tantalum; D013718:Tensile Strength; D014025:Titanium; D015040:Zirconium
D000497:Alloys; D009556:Niobium; D013635:Tantalum; D015040:Zirconium; D014025:Titanium