Estudo da influência de processamentos termomecânicos e do nióbio na estrutura, microestrutura e propriedades mecânicas selecionadas de novas ligas do sistema Ti-25Ta-Nb visando aplicações biomédicas
Data
2022-03-09
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Universidade Estadual Paulista (Unesp)
Resumo
No Brasil há um crescimento constante na demanda de próteses ortopédicas, decorrente do aumento da expectativa de vida. A liga mais utilizada atualmente como biomaterial é a Ti-6Al-4V (114 GPa), porém, estudos indicam que o alumínio e o vanádio podem causar reações adversas ao organismo. Outro problema a ser ressaltado é a diferença do módulo de elasticidade que é 2 a 4 vezes maior que o osso (35 GPa), ocasionando a reabsorção óssea. Logo, a necessidade de se desenvolver novas ligas de Ti que sejam inofensivas ao organismo, e que melhorem a qualidade de vida dos pacientes se torna eminente. O presente trabalho tem como objetivo desenvolver novas ligas de Ti com a presença de elementos β-estabilizadores como tântalo e nióbio, o sistema Ti-25Ta-xNb (x=10,20,30,40% em peso) foi analisado a partir da influência de tratamentos termomecânicos, como de homogeneização e solubilização, realizados respectivamente após o processo de fusão, e após o processamento de laminação. Em paralelo, será verificada a influência do nióbio como elemento substitucional. Para estudar diferentes fatores das ligas, foram realizadas caracterizações química, estrutural, microestrutural e mecânica, além da biocompatibilidade do sistema desenvolvido. A caracterização química indicou que ligas apresentam boa homogeneidade e estequiometria adequada. Os difratogramas de raios X e as micrografias eletrônicas de varredura e ópticas apresentam resultados que corroboram entre si e indicam a presença das fases martensíticas α’, α” e fase β nas ligas com Ti-25Ta-10Nb e Ti-25Ta-20Nb. As ligas Ti-25Ta-30Nb e Ti-25Ta-40Nb apresentam exclusivamente picos característicos e grãos equiaxiais da fase β, com isso estas ligas consideradas β apresentam menores valores de dureza em comparação às demais ligas do sistema. Todas as composições desenvolvidas neste trabalho são atóxicas ao organismo e apresentam baixo módulo de elasticidade quando comparadas ao Ti-cp e a liga Ti-6Al-4V. A liga Ti-25Ta-20Nb na condição solubilizada a liga que apresenta menor valor de módulo de elasticidade (66 GPa). Ao fim pode-se considerar que o sistema Ti-25Ta-xNb apresenta resultados promissores e pode ser utilizado para fins biomédicos.
In Brazil, there is a constant growth in the demand for orthopedic prostheses due to life expectancy. The alloy most used today as a biomaterial is Ti-6Al-4V (114 GPa); however, studies indicate that aluminum and vanadium can cause adverse reactions to the body. Another problem to be highlighted is the difference in the modulus of elasticity around 2 to 4 times greater than that of bone (35 GPa), which causes bone resorption. Therefore, the need to develop new Ti alloys that are harmless to the organism and improve patients' quality of life becomes imminent. Thus, the present work aims to create new Ti alloys with the presence of β-stabilizing elements such as tantalum and niobium, the Ti-25Ta-xNb system (x=10,20,30,40% by weight) was analyzed at from the influence of thermomechanical treatments, such as homogenization and solubilization, carried out respectively after the melting process, and after the lamination process. Together, the influence of niobium as a substitutional element will be verified. In order to study different factors of the alloys, chemical, structural, microstructural, and mechanical characterizations were carried out, in addition to the biocompatibility of the developed system. The chemical characterization indicated that alloys present good homogeneity and adequate stoichiometry. X-ray diffractograms and scanning electron and optical micrographs present results that corroborate each other and indicate the presence of martensitic α', α” and β phases in alloys with Ti-25Ta-10Nb and Ti-25Ta-20Nb. The Ti- 25Ta-30Nb and Ti-25Ta-40Nb alloys have exclusively characteristic peaks and equiaxed grains of the β phase, so these alloys considered β have lower hardness values than the other alloys in the system. All the compositions developed in this work are non-toxic to the organism and have a low modulus of elasticity when compared to Ti-cp and Ti-6Al- 4V alloy. The solubilized alloy Ti-25Ta-20Nb has the lowest modulus (66 GPa). In the end, it can be considered that the Ti-25Ta-xNb system presents promising results and can be used for biomedical purposes.
In Brazil, there is a constant growth in the demand for orthopedic prostheses due to life expectancy. The alloy most used today as a biomaterial is Ti-6Al-4V (114 GPa); however, studies indicate that aluminum and vanadium can cause adverse reactions to the body. Another problem to be highlighted is the difference in the modulus of elasticity around 2 to 4 times greater than that of bone (35 GPa), which causes bone resorption. Therefore, the need to develop new Ti alloys that are harmless to the organism and improve patients' quality of life becomes imminent. Thus, the present work aims to create new Ti alloys with the presence of β-stabilizing elements such as tantalum and niobium, the Ti-25Ta-xNb system (x=10,20,30,40% by weight) was analyzed at from the influence of thermomechanical treatments, such as homogenization and solubilization, carried out respectively after the melting process, and after the lamination process. Together, the influence of niobium as a substitutional element will be verified. In order to study different factors of the alloys, chemical, structural, microstructural, and mechanical characterizations were carried out, in addition to the biocompatibility of the developed system. The chemical characterization indicated that alloys present good homogeneity and adequate stoichiometry. X-ray diffractograms and scanning electron and optical micrographs present results that corroborate each other and indicate the presence of martensitic α', α” and β phases in alloys with Ti-25Ta-10Nb and Ti-25Ta-20Nb. The Ti- 25Ta-30Nb and Ti-25Ta-40Nb alloys have exclusively characteristic peaks and equiaxed grains of the β phase, so these alloys considered β have lower hardness values than the other alloys in the system. All the compositions developed in this work are non-toxic to the organism and have a low modulus of elasticity when compared to Ti-cp and Ti-6Al- 4V alloy. The solubilized alloy Ti-25Ta-20Nb has the lowest modulus (66 GPa). In the end, it can be considered that the Ti-25Ta-xNb system presents promising results and can be used for biomedical purposes.
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Palavras-chave
Biomateriais, Ligas de titânio, Nióbio, Módulo de elasticidade, Materiais biomédicos, Biomaterials, Titanium alloys, Niobium, Modulus of elasticity