Creep evaluation of metallic materials by ultrasonic and metallurgical parameters

Determination of the status of materials is important in order to improve the availability of industrial plants and extend their lifetime. This paper describes ultrasonic techniques orientated towards characterisation of the structure of materials by correlation with wave propagation parameters, such as velocity, attenuation and energy. On the basis of the tests performed it may be deduced that creep damage gives rise to a reduction in ultrasonic velocity, an increase in attenuation and a decrease in the energy of signals at high frequencies.