Study On The Microstructure And Property Of New β-Ti28Nb24.5Zr Alloy For Biomedical Applications

Ti28Nb24.5Zr alloy is an excellentβ-type biomedical Titanium alloy that was developed by American scientists in recent years. It has been enrolled into international surgical implant's standard and applied widely. The low modulus of elasticity, higher tensile strength, good plasticity and toughness are the most important premise for surgical implants and orthopedic devices. In order to promote application of Ti28Nb24.5Zr alloy in China, in this paper, the microstructures of alloy have been studied and alloy has been cool-rolled after homogenization treatment, then the solution treatment and aging treatments of alloy have been carried on. Different aging temperatures affecting on the mechanics properties (stress, hardness, elastic modulus) of alloy have been studied systemically. Researching the processes and law of low modulus and high stress, discussing superficially the causticity of alloy, as a result, At no impurity, the microstructure of alloy wasβ-phase after casting and Solution treatment. The microstructure of alloy wasβ-phase and a small quantity ofα-phase after homogenization treatment. The process property of alloy was excellent. The alloy was treated with solution treatment and aging treatment after cool rolling. When increasing the temperature of aging, more fragileω-phase was found inβ-phase, so the stress of alloy was enhanced. The stress of alloy will decline not until too machω-phase was found. Partω-phase in alloy was turned intoα-phase with continuing increasing aging temperature, so the stress of alloy was enhanced slightly again. The hardness of alloy was increased with much higher aging temperature, especially at 460℃reaching at the hardest. Partω-phase in alloy was turned intoα-phase with continuing increasing aging temperature, so the hardness of alloy gone down. at impurity, a small quantity ofα-phase was found in the casting microstructure of alloy while a great deal ofα-phase andω-phase was found after homogenization treatment, so the process property of alloy was bad. Resisting causticity was studied after alloy was treated with two processes. The phase and different surface appearances of alloy were observed with microscope and SEM. Anode polarization curves were measured by electrochemistry corrosion and resisting causticity was analyzed in different condition and solution. As a result, the alloy has excellent resisting causticity.