Influence of heating rate and aging temperature on omega and alpha phase precipitation in Ti-35Nb alloy

Autor(es)

de Mello, Mariana G. ^[1] ; Dainese, Beatriz P. ^[2] ; Caram, Rubens ^[1] ; Cremasco, Alessandra ^[2]

Afiliação do(s) autor(es)

^[1] Univ Campinas UNICAMP, Sch Mech Engn, Rua Mendeleiev 200, BR-13083860 Campinas, SP - Brazil

^[2] Univ Campinas UNICAMP, Sch Appl Sci, Rua Pedro Zaccaria 1300 Jardim Santa Luiza, BR-13484350 Limeira, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS CHARACTERIZATION; v. 145, p. 268-276, NOV 2018.
• Citações Web of Science: 0

Resumo

Metastable beta Ti alloys based on Nb exhibit features that make them suitable for load-bearing biomedical applications, so it is crucial to evaluate their phase transformation and properties. This paper discusses the effects of aging heat treatments on the microstructure, phase transformation and mechanical behavior of Ti-35Nb alloy. Samples were solution heat treated in the beta field, quenched and aged under different conditions of heating rates, isothermal aging temperature and isothermal aging time. To enhance the alloy's mechanical behavior, thermal analysis and high temperature X-ray diffraction experiments coupled with Vickers hardness tests were employed to determine the temperature range of isothermal omega phase precipitation, as well as alpha phase precipitation temperature, thereby providing information to optimize aging heat treatment conditions. Results indicate that Ti-35Nb alloy subjected to a heating rate of 30 degrees C/min and an isothermal aging temperature of 500 degrees C applied for 4 h would ensure high mechanical strength and low elastic modulus. The application of these aging conditions led to a microstructure consisting of very refined a phase precipitates homogeneously dispersed in the beta phase matrix, presenting an ultimate tensile strength of 972 MPa, elongation of 7.5% and elastic modulus of 78 GPa, making this aged alloy a promising candidate for biomedical applications. These results shed light on the correlations between phase transformations, microstructure and mechanical behavior in high solute content Ti Nb alloys for biomedical applications. (AU)

• Processo FAPESP: 14/00159-2 - Estudo eletroquímico de ligas de Ti beta metaestáveis revestidas com filmes nanoestruturados de TiO2
• Beneficiário: Alessandra Cremasco
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/24693-3 - Precipitação Não-clássica da Fase Alfa em Ligas Ti-Nb-Fe e Ti-Nb-Fe-Sn
• Beneficiário: Rubens Caram Junior
• Modalidade de apoio: Auxílio à Pesquisa - Regular