Abstrakt
The influence of thermo-mechanical treatment on microstructure and mechanical properties of T-35Nb-6Ta has been studied. The thermo-mechanical treatmentwas chosen to correspond to the production of wire with suitable mechanical properties for dental implants.
After casting the alloy was hot forged (700-900 oC), solution treated (850 oC/30 min, water quenched) and cold swaged (reductions up to 91%). The annealing (700 oC/3 h/furnace) or aging (450 oC/ 8 h/furnace) was used as final heat treatment.
The microstructure was studied by using light microscopy, scanning electronmicroscopy, transmission electron microscopy and XRD analysis. Cold swaging introduces microstructure consisting of highly deformed β-phase grains with dislocation tangles and twins,which ensures high tensile strength about 820 MPa, lowYoung's modulus (~50 GPa) and good ductility ~10%.
Subsequent aging increases tensile strength (1000 MPa) as well as Young's modulus (75 GPa) without diminishing ductility. Annealing at 700 oC slightly decreases tensile strength (730 MPa) and increases the ductility and Young's modulus (17% and 62 GPa respectively).
The mechanical properties attained recommend the thermo-mechanical treatment for production of wires for dental implants.