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Abstract:Objective:Titanium and titanium alloys represent generally accepted metallic biomaterials for clinical dentistry and dental implantology. In th is paper, we present a Ti-35.5Nb-5.7Ta alloy with a special respect to its microstructure and mechanical characteristics, such as Young modulus of elasticity. Methods:Three thermal treatments differing in temperature and time of annealing were used during the Ti-35.5Nb-5.7Ta processing in order to evaluate the effects of ageing, melting annealing, and annealing on mechanical characteristics and microstructure. Results: Using microscopy, the alloy was analyzed and the differences in shares of beta phase grains, alpha particles and precipitates evaluated. The three thermal treatments were evaluated also from technological point of view. Conclusion:The following thermal treatment was found optimal for the Ti-35.5Nb-5.7Ta alloy: melting annealing at 800 °C for 0.5 hour followed by a cold swaging with a 52-79 % deformation, and fi nal hardening at 500 °C for 2 hours in water (Tab. 2, Fig. 3, Ref. 24).Text in PDF www.elis.sk.

The paper is concerned with the relation between temperature and critical crack length for the initiation of a brittle crack unstable propagation at the yield strength level stress. For the purpose of calculation, results of dynamic fracture toughness test were applied; the experiment was supplemented with measuring stress and deformation characteristics in a determined test temperature range. For comprehensive assessment of test temperature effects, a fractographic analysis of fracture surfaces was conducted.