Influence of Nanoalumina Particles on the Static and High-Cycle Fatigue Properties of Peel-Loaded Adhesive-Bonded Joints

Abstract

Results of research are aimed at determining the possibility of improving the static and fatigue properties of peel-loaded adhesive-bonded joints of S235JR steel with an alumina nanopowder dispersed in an epoxy adhesive. The static properties were assessed in a T-peel test. The high-cycle fatigue strength tests were carried out on an electromagnetic inductor with the resonance frequency of the joint specimen. High-cycle fatigue was analyzed at the limited number of cycles 2 10⁶. The tests were conducted on the specimens bonded with an Epidian 57 epoxy adhesive and a PAC hardener, whose properties were modified through the introduction of an alumina nanopowder. Four versions of the filled epoxy adhesive were examined, 0.5, 1.5, 2, and 3 wt.% of the dried nanopowder were dispersed in the epoxy adhesive. Fatigue strength tests revealed a significant improvement of the fatigue lifetime of adhesive-bonded joints due to the addition of fillers. In the best case a more than five-fold increase in the fatigue lifetime was obtained (from 199,500 to 1000,000 cycles). The fatigue strength for the best case increased by about 19%.