Efeito do oxigênio intersticial no módulo de elasticidade de Ligas Ti-15Mo-xZr(x=5,10,15%p)
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Data
2014-08-29
Autores
Vicente, Fábio Bossoi [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O desenvolvimento biomateriais metálicos para uso ortopédico depende muito da região corpórea pretendida. Para próteses ortopédicas, espera-se que um biomaterial seja biocompatível, não-cancerígeno, resistente à corrosão e possua baixo desgaste. Estas propriedades são todas dependentes da superfície do material. Além destas propriedades espera-se que a prótese tenha baixo módulo de elasticidade, que é uma propriedade do bulk, do material. Neste trabalho, ligs do sistema temário Ti-15Mo-xZr(x=5,10,e15%p) foram estudadas em função da concentração do elemento substitucional e em função do oxigênio intersticial, para a compreensão dos mecanismos metalúrgicos e subsequente redução do módulo elástico, relacionando a resposta mecânica das ligs com suas microestruturas. Para fundamentar a discussão, a qualidade das amostras foi verificada por análise química quantitativa, análise de gases e EDS. Estas análises iniciais comprovaram que a estequiometria das amostras está satisfatória e o processo de fusão produziu ligas homogênicas. Para o relacionamento entre propriedades mecânicas e microestrutura foram realizadas medidas de difração de raios X, análise pelo método de Rietveld, microscopia óptica e eletrônica de varredura, microdureza, módulo estático e atrito interno. As ligas possuem predominantemente fase B (com estrutura cúbica de corpo centrado), com pequenas concentrações da fase martensitica (com estrutura hexagonal compacta) nas amostras com maiores concentrações de oxigênio em solução sólida. De modo geral a adição do oxigênio aumenta a dureza das ligas, em função da dificuldade de movimentos das discordâncias, fazendo com que a dureza aumente com a concentração desse soluto. Nos ensaios realizados, não se observa alteração significativa no módulo elástico em função da concentração de oxigênio, que se mostrou mais sensível aos tratamentos termomecânicos submetidos...
The development of metallic biomaterials for orthopedic applications is highly dependent on the body part under consideration. Biomaterils used in orthopedic prostheses should be biocampatible, noncarcinogenic, and corrosion resistant, with low wear rates; these properties are dependent on the surface characteristics of the materials. In additon, a prosthesis should have a low modulus of elasticity, which is a property of material bulk. In this work, the ternary Ti-15Mo-xZr (x=5, 10 and 15 wt%) alloys are studied as a function of the concentration of substitutional and interstitial elements in order to understand the metallurgical mechanisms and subsequent reduction of the elastic modulus, relating the mechanical properties of the alloys with their microstructures. Initially, the quality of the samples was verified via quantitative chemical analysis, gas analysis, and EDS. These initial analyses showed that the stoichiometry of the samples was satisfactory and that the melting process produced homogeneous allys without any precipitate. The following were performed in order to examine the relationship between the mechanical properties of the alloys and their microstructures: X-ray diffraction with Rietveld analysis: optical and electron scanning microscopy: and investigations of hardness, elastic modulus (using impulse excitation), and internal friction. The alloys were found to comprise predominantly B phase (with body-centered cubic structure), with small concentrations of martensitic phase (with hexagonal compact structure), after quenching the samples in an oxygen-controlled atmosphere. In general, an increase in oxygen concentration makes it difficult for dislocations to move, thereby increasing the hardness of the alloys. No significant change was observed in the elastic modulus as a function of oxygen concentration in the conducted tests; this property was found to be more sensitive to thermomechanical treatments. Nonetheless, the...
The development of metallic biomaterials for orthopedic applications is highly dependent on the body part under consideration. Biomaterils used in orthopedic prostheses should be biocampatible, noncarcinogenic, and corrosion resistant, with low wear rates; these properties are dependent on the surface characteristics of the materials. In additon, a prosthesis should have a low modulus of elasticity, which is a property of material bulk. In this work, the ternary Ti-15Mo-xZr (x=5, 10 and 15 wt%) alloys are studied as a function of the concentration of substitutional and interstitial elements in order to understand the metallurgical mechanisms and subsequent reduction of the elastic modulus, relating the mechanical properties of the alloys with their microstructures. Initially, the quality of the samples was verified via quantitative chemical analysis, gas analysis, and EDS. These initial analyses showed that the stoichiometry of the samples was satisfactory and that the melting process produced homogeneous allys without any precipitate. The following were performed in order to examine the relationship between the mechanical properties of the alloys and their microstructures: X-ray diffraction with Rietveld analysis: optical and electron scanning microscopy: and investigations of hardness, elastic modulus (using impulse excitation), and internal friction. The alloys were found to comprise predominantly B phase (with body-centered cubic structure), with small concentrations of martensitic phase (with hexagonal compact structure), after quenching the samples in an oxygen-controlled atmosphere. In general, an increase in oxygen concentration makes it difficult for dislocations to move, thereby increasing the hardness of the alloys. No significant change was observed in the elastic modulus as a function of oxygen concentration in the conducted tests; this property was found to be more sensitive to thermomechanical treatments. Nonetheless, the...
Descrição
Palavras-chave
Ligas de titanio, Materiais biomédicos, Rietveld, Metodo de, Titanium alloys
Como citar
VICENTE, Fábio Bossoi. Efeito do oxigênio intersticial no módulo de elasticidade de Ligas Ti-15Mo-xZr(x=5,10,15%p). 2014. 135 f. Tese (doutorado) - Universidade Estadual Paulista Julio de Mesquita Filho, Faculdade de Ciências, 2014.