Caracterização microestrutural e mecânica da liga Ti10Mo8Nb6Zr para aplicações biomédicas
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Data
2019-02-22
Autores
Pereira Júnior, Adelvam
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Titânio e suas ligas têm sido amplamente aplicados em materiais biomédicos devido as suas excelentes propriedades de volume (relação massa específica e resistência mecânica), biocompatibilidade e resistência à corrosão. As ligas de titânio utilizadas comercialmente são a Ti CP (comercialmente puro) e Ti6Al4V e apesar de muito utilizadas apresentam problemas de citotoxicidade e dessa maneira se faz importante o desenvolvimento de novas ligas que levem a substituição das mesmas. Ligas de titânio do tipo beta têm sido amplamente exploradas devido a sua excelente relação baixo peso específico e módulo de elasticidade, fator que reduz o efeito de Stress Shielding. O objetivo deste trabalho foi processar e caracterizar uma liga de titânio do tipo beta com composição Ti10Mo8Nb6Zr (%m) visando aplicações biomédicas. Os lingotes da liga foram obtidos em um forno de fusão a arco voltaico com atmosfera inerte de gás argônio. A liga foi tratada em um forno tubular a vácuo a 1000ºC por 24 horas para garantir a homogeneidade química, forjada a frio em barras de 9,60 mm de diâmetro e tratadas termicamente novamente a 950°C por 2 horas, seguido de resfriamento em água. A microestrutura e as fases presentes de cada etapa do processamento da liga foram investigadas por Microscopia Óptica (MO), Difração de Raios X (DRX) e Calorimetria Exploratória Diferencial (DSC). Sendo possível constatar a presença da fase beta e a presença de uma possível fase metaestável a ω, comprovando o diagrama de previsão para a liga. A caracterização mecânica da liga foi realizada por meio de microdureza, técnica de excitação por impulso e ensaio de tração, observando-se para a liga um baixo módulo de elasticidade (82,9 GPa) comparado as ligas comerciais. Nos estudos em relação a resistência a corrosão a liga Ti10Mo8Nb6Zr apresentou maior resistência a corrosão que Ti CP. As análises in vitro mostraram viabilidade do crescimento celular sendo para tanto, não citotóxica.
Titanium and its alloys have been widely applied in biomedical materials because of their excellent volume properties (specific mass ratio and strength), biocompatibility and corrosion resistance. The titanium alloys used commercially are Ti CP (commercially pure) and Ti6Al4V, although they are widely used they present problems of cytotoxicity (Ti6Al4V) and high Young's modulus (Ti CP) and in this way it is important to develop new alloys that lead to their replacement. Beta-type titanium alloys have been extensively explored because of their excellent low specific weight ratio and low modulus of elasticity, which reduces the effect of Stress Shielding, besides absence of problems with citotoxicity. The purpose of this study was processing and characterization of the new beta-titanium alloy Ti10Mo8Nb6Zr (%wt) for biomedical applications. The ingots were obtained in an eletric arc furnace with an inert atmosphere of argon gas. They were heat treated in a tubular vacuum furnace at 1000°C for 24 hours to ensure chemical homogeneity, cold worked in rods with 9.60 mm diameter, and solubilized in tubular furnace under vacuum at 950°C for 2 hours followed by cooling in water. The microstructure and the phases present in each step of the alloy processing were investigated by The microstructure and the phases present at each step of the processing of the alloy were investigated by optical microscopy, X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). It was possible to verify the presence of the beta phase and the presence of a possible metastable phase at ω, proving the prediction diagram for the alloy. The mechanical characterization of the alloy was performed by microhardness, impulse excitation technique and tensile test, and it was observed a low modulus of elasticity (82.9 GPa) compared to commercial alloys. The Ti10Mo8Nb6Zr alloy showed to be more resistant to corrosion than commercial alloy. In vitro analyzes showed cell growth viability being non cytotoxic.
Titanium and its alloys have been widely applied in biomedical materials because of their excellent volume properties (specific mass ratio and strength), biocompatibility and corrosion resistance. The titanium alloys used commercially are Ti CP (commercially pure) and Ti6Al4V, although they are widely used they present problems of cytotoxicity (Ti6Al4V) and high Young's modulus (Ti CP) and in this way it is important to develop new alloys that lead to their replacement. Beta-type titanium alloys have been extensively explored because of their excellent low specific weight ratio and low modulus of elasticity, which reduces the effect of Stress Shielding, besides absence of problems with citotoxicity. The purpose of this study was processing and characterization of the new beta-titanium alloy Ti10Mo8Nb6Zr (%wt) for biomedical applications. The ingots were obtained in an eletric arc furnace with an inert atmosphere of argon gas. They were heat treated in a tubular vacuum furnace at 1000°C for 24 hours to ensure chemical homogeneity, cold worked in rods with 9.60 mm diameter, and solubilized in tubular furnace under vacuum at 950°C for 2 hours followed by cooling in water. The microstructure and the phases present in each step of the alloy processing were investigated by The microstructure and the phases present at each step of the processing of the alloy were investigated by optical microscopy, X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). It was possible to verify the presence of the beta phase and the presence of a possible metastable phase at ω, proving the prediction diagram for the alloy. The mechanical characterization of the alloy was performed by microhardness, impulse excitation technique and tensile test, and it was observed a low modulus of elasticity (82.9 GPa) compared to commercial alloys. The Ti10Mo8Nb6Zr alloy showed to be more resistant to corrosion than commercial alloy. In vitro analyzes showed cell growth viability being non cytotoxic.
Descrição
Palavras-chave
Ligas de titânio, Caracterização microestrutural, Resistência a corrosão, Estudos in vitro, Aplicação biomédica, Titanium alloys, Microstructural characterization, Corrosion resistance, In vitro studies, Biomedical application, Materiais resistentes a corrosão, Materiais biomédicos, Microestrutura