Becky Sheridan, Dr. John Dillard, and Dr. Nick Shephard
National Science Foundation and Technology Center:
High Performance Polymeric Adhesive and Composites, and
Department of Chemistry
Virginia Polytechnic Institute and State University
Blacksburg, Virginia


Double cantilever beam (DCB), or wedge, specimens were used to investigate the durability of adhesively bonded aluminum. The polymeric adhesives of interest were a two part epoxy and an acrylic adhesive. The 6061 aluminum alloy was subjected to two surface treatments: abrasion followed by a base/acid cleaning, and the same treatment followed by phosphoric acid anodization (PAA). The effect of surface treatment on durability was investigated by immersion in water at temperatures of 4 deg. C, 33 deg. C, 66 deg. C and 100 deg. C. Crack growth in the wedge specimens was the major indicator of bond durability. The specimens bonded with the acrylic adhesive had a slower growth rate than those bonded with the epoxy. The PAA surface treatment resulted in the slower crack growth rate, and most specimens failed more readily at higher temperatures. When the wedge tests were concluded, the surface morphology was determined using scanning electron microscopy (SEM) and the mode of failure was determined with X-ray photoelectron spectroscopy (XPS). Failure modes observed visually must be verified by XPS surface analysis. It is the intent to use wedge test data in the construction of durability models.