Residual Strength Fluctuation of Adhesively Bonded Joints Subjected to High Temperature in Argon Environment

Abstract

The strength fluctuation of adhesively bonded joints subjected to a high temperature condition has experimentally been investigated. The specimens of a single-lap joint bonded with an epoxy adhesivewere kept in Argon gas environment at 150℃ for up to 100 h and tested in terms of lap-shear strength.In addition, the other type of specimens, which have cured adhesive layers on the same substrate as the single-lap joint specimens, were prepared and kept in the same environment and temperature in order to investigate the color change of the adhesive layers due to oxidation at a high temperature.The joint strengths did not decrease but slightly increase after the exposure in Argon environment of a high temperature as the same as in air. The color of an adhesive layer confined in the joints didnot change, the marginal area of the adhesive layer, however, exhibited color change from white to yellow. The cured adhesive specimens on the substrates also exhibited the same color change.