ABSTRACT
Obviously, there is no single mechanism of aluminum-bonded joint failure, since there is a possibility for disrupting the bond in each of the separate parts of a joint. If the cohesive strength of the adherend is less than the stress imposed, then a failure will undoubtedly occur in that cross-sectional area. On the other hand, a joint failure will be similarly forecast if the imposed stress exceeds the bulk cohesive strength of the adhesive. Then there is the exceedingly complex chemistry of the interphase to deal with, where the primary forces of ionic, metallic, or covalent natures can be contributing to the jointure. Also, the secondary forces of van der Waals are always present to make their particular contribution to establishing the bond. Then there are the factors of overall joint strength that relate specifically to the morphology of the adherend surfaces and the rheological properties of the adhesive materials as cured. Finally, there is the distinct possibility that the various joint parts have been attacked and diminished in properties by the weathering environment, which may be further complicated by stress simultaneously imposed on the joint.
