de Mello, Mariana G.
Costa, Fernando H.
Total Authors: 6
 Univ Campinas UNICAMP, Escola Ciencias Aplicadas, BR-13484350 Limeira, SP - Brazil
 Univ Campinas UNICAMP, Escola Engn Mecan, BR-13083860 Campinas, SP - Brazil
Total Affiliations: 2
MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS;
Web of Science Citations:
The mechanical behavior of metastable beta Ti alloys can be controlled through heat treatments. Thus, the relationship between the precipitation of alpha phase and the mechanical properties of these alloys is of special interest. In this work, the microstructure evolution of Ti-30Nb-3Fe alloy during aging heat treatments was evaluated using optical microscopy, scanning electron microscopy and X-ray diffraction. Moreover, Vickers hardness and elastic modulus were measured as a function of aging time. Finally, the ultimate strength and ductility of the alloy aged at 500 degrees C was assessed by tensile tests. In comparison to a Ti-30Nb alloy, the addition of Fe lowered the beta-transus temperature, decreased the martensite start temperature to a value below room temperature, increased the precipitation temperature and reduced the dissolution temperature of omega phase, and lastly, decreased the alpha phase precipitation temperature. Low heating rates enabled isothermal omega phase precipitation and growth, providing favorable conditions for alpha phase precipitation and increasing the amount of alpha phase precipitates. Compared to the solution heat-treated and water-quenched condition, aging heat-treated Ti-30Nb-3Fe alloy presented higher Vickers hardness and mechanical strength, without significant loss of ductility. (AU)