Experimental determination of the peel adhesion strength for metallic foils

This work addresses the problem of experimental measurement of peel adhesion in cases where a non-recoverable (plastic) deformation energy of the peeled foil, plus frictional losses, constitutes a significant portion of the total peel energy. In standard tests, when the true adhesion strength is desired, the plastic energy has to be calculated and deducted from the total energy. Several studies have been dedicated to the modelling and calculation of the energy dissipated through plastic deformation so that the net adhesion energy could be deduced. These calculations are cumbersome and impractical for general use. A simple experimental technique for the determination of the net adhesion strength is proposed. Experimental results with similar to 0.1 mm thick foils of stainless steel, nickel, and titanium confirm the theoretical predictions regarding the energy balance during peeling. Using the proposed methodology, there is no need to calculate or otherwise determine the deformation energy losses of the peeled foil or the frictional dissipation. The method is not limited to a particular material and can be used successfully for strain hardening plastic as well as metallic foils. Peel tests on adhesively bonded specimens of stainless steel and nickel and of a thermal spray-coated Ti alloy foil were carried out to demonstrate the applicability of the proposed method.