AplicaÃÃo dos mÃtodos de pulso-eco e resonÃncia acÃstica para caracterizaÃÃo nÃo destrutiva de propriedades elÃsticas e microestruturais de vidros especiais e aÃo ferrÃtico degradado por fluÃncia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The elastic properties, homogeneity, attenuation of the propagation of ultrasonic waves and associated structure with some types of special glass were analyzed with the pulse-echo method. A total of seven samples of glass containing neodymium, lead, zirconium and niobium, as additives were analyzed. As a result, elastic constants such as coefficient of Poisson, modules of compressibility, modules of Young and structural parameter hardness, acoustic impedance, fractal bond connectivity, anisotropy factor and Debye temperature were determined by measuring longitudinal and transversal wave propagation and density values with excellent precision. Furthermore, five samples of ferritic steel containing molybdenum and chromium as alloying elements and that suffered creep were analyzed using the technique ultrasonic acoustic resonance. A non contact EMAT transducer and EMAR technique is convenient to the study of elastic properties of metallic materials at high temperature were applied for ultrasonic measures. The samples were part of a boiler steam and were collected in different positions in relation to the fire. Changes in the structure of the samples were analyzed using the most advanced techniques of characterization like MEV, EDX and measure of hardness. The results were compared with the results of elastic constants such as coefficient of Poisson, modules of compressibility, modules of Young and hardness obtained with ultrasonic acoustic resonance

ASSUNTO(S)

pulse-echo glass aÃo ferrÃtico ultra-som pulso-eco ultrasonic vidros acoustic resonance ferritic steel engenharia mecanica ressonÃncia acÃstica

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