Effects of the microstructure of pretreated aluminum joints AA2024 T3T3 on the ultrasonic evaluation of adhesion

This paper is concerned with the ultrasonic characterization of the adhesion in a structural bond subjected to various surface pretreatments. The aim is: (a) to know if the non destructive evaluation allows to distinguish three types of pretreatments and (b) to optimize the procedure (e.g. time of steeping, concentration of the solution, temperature) for a given surface treatment in order to obtain a better durability of structural joints. This distinction is based on the measurement of the cutoff-frequencies of the guided waves. The comparison with two rheological models leads to a classification of the pretreatments according to their effectiveness.