In this study, the stress state of metal coating on a steel substrate under tensile straining was investigated by with finite element modelling with the aim of better understanding the mechanism of delamination for the coating. The investigations showed cracking and delamination of the coating by the application of uniaxial tensile strain to the substrate. Due to interfacial stress crack appeared in the coating-substrate interface. The stress measurements in coated substrate, using FEA, indicated interfacial shear and peeling stresses at the interface near the edges of the coating under tensile load. When tensile stress is applied externally on the coated substrate, the coating exhibits multiple cracking perpendiculars to the tensile direction, and then interfacial debonding occurs. A good agreement is found between the modelling approach and the corresponding experimental tensile tests of the coated specimens. The effect of coating thickness on the evolution of the stress distribution was also studied. The cracking and delamination of the coatings with a thickness ranging from 90 to 160 m was studied by tensile test experiments. The estimation of the stress distribution and concentration at the interface during these experiments allows the failure stress of the coating in the interface coating–substrate to be evaluated.
- Chen Z., Zhou K., Lu X., Lam Y.C. (2014): A review on the mechanical methods for evaluating coating adhesion. In: Acta Mech 225 (2), pp. 431 – 452.
- Dolgov N.A. (2016): Analytical methods to determine the stress state in the substrate–coating system under mechanical loads. In: Strength of materials 48 (5), pp. 658 – 667.
- Dolgov N. A., Smirnov, I. V., Besov A. V. (2015): Studying the elastic properties and adhesive strength of plasma-sprayed double-layer coatings during tensile tests. In: Powder Metallurgy and Metal Ceramics 1–2 (54), pp. 40 – 46.
- Zhang S., Wang Y.S., Zeng X.T. et al. (2007): Evaluation of interfacial shear strength and residual stress of sol–gel derived fluoridated hydroxyapatite coatings on Ti6Al4V substrates. In: Engineering Fracture Mechanics 74, pp. 1884 –1893.
- Besov A.V., Maslyuk V.A., Stepanchuk A.N. et al. (2005): Cobalt-chromium powder alloys and retention coatings made from them for orthopaedic stomatology. In: Powder Metallurgy and Metal Ceramics 5–6 (44), pp. 207 – 210.
- Besov А.V., Morozov V.V. (2002): Opportunities of use of plasma technology in medicine [in Ukrainian]. In: Metal Science and Treatment of Metal 3, pp. 62 – 66.
- Dolgov N.A., Lyashenko B.A., Veremchuk V.S., Dmitriev Yu.V. (1995): Determining elasticity characteristics for protective coatings. In: Strength of Materials 27 (7), pp. 392 – 394.