Correlação entre transformações de fases e comportamento mecanico de ligas Ti-Nb-Sn e sua aplicação na concepção de implantes ortopedicos com propriedades otimizadas / Correlation between phase transformations and mechanical behavior of Ti-Nb-Sn alloys and its applications in the design of orthopedic implants with optimized characteristics

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

β type Ti alloys exhibit versatility in terms of mechanical properties, which can be tailored by using specific heat treatment conditions. In this work, Ti-Nb-Sn alloy samples were prepared, processed and characterized, aiming to produce femoral stems of total hip prostheses. The research included evaluations of phase transformations during heat treatments as well as analyses of the effect of such heat treatments on the microstructure and mechanical behavior. It also included the proposition of a manufacturing process of such stem using cold forging process and application of specific heat treatment conditions according to the component mechanical requirements. The results obtained allowed one to describe martensite decomposition as well as β, ω e α phases precipitation. Such information has been applied in the selection of optimized conditions that allow successful cold forging, providing undesirable defects-free parts. Also, application of specific heat treatment conditions led to the optimization of the stem mechanical behavior. The stem upper section, which is usually subjected to higher mechanical stress, was submitted to aging heat treatment, resulting in higher mechanical strength. On the other hand, the lower section, which must have compatible performance with bone elastic deformation, was processed in a different manner to result in low elastic modulus.

ASSUNTO(S)

ligas de titanio implantes ortopédicos heat treatment mechanical properties tratamento termico titanium alloys propriedades mecanicas orthopedic implants

ACESSO AO ARTIGO

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