Ultrasonic absorption measurement

For materials used under extreme conditions, the recognition of damage caused by materials aging is of great importance. In order to avoid failure of components during operation, many parts are replaced earlier than necessary, i.e., while they are still intact, leading to higher costs that could be reduced if the degree of damage in the component material could be determined nondestructively. Any changes in the microstructure of a material resulting from the fatigue process affect the absorption of ultrasonic waves in the material. Thus, quantitative measurement of ultrasonic absorption could allow an indirect measurement of fatigue damage, and therefore be of interest to NDE applications. The aim of our research is to study the influence of fatigue damage on ultrasonic absorption in order to identify the mechanisms responsible for the increase of absorption with increasing degree of damage. This information may then be used to develop NDE techniques for detection of fatigue damage.