Effects of tensile and compressive in-plane stress fields on adhesion in laser induced delamination experiments

In this work, the adhesion of a polymer coating on steel substrate subjected to uniaxial tensile plastic deformations was studied with the laser induced delamination technique. A decrease in the practical work of adhesion has been measured as the deformation of the substrate progressed. Moreover, it was observed that the deformation of the metal substrate introduced in-plane stresses in the polymer coating. Delamination was studied under compressive or tensile in-plane stresses. The model presented enabled to derive from the experimental data not only the practical work of adhesion but also the magnitude and the character (tensile or compressive) of the in-plane stress. The strain fields of the metal substrate during plastic deformation and after the elastic relaxation were monitored with a digital image correlation analysis system. The measured strain fields were confronted to the in-plane stresses obtained from the delamination experiments.