Tensile properties, shear strength calculation and cracking behavior of bulk composite comprised of thick HVOF sprayed coating and steel substrate

The adhesion strength between coating and substrate is the critical factor to attain high wear resistance and other properties of the coating. In this study, a novel method for evaluating the adhesion strength is employed to measure the shear strength of the interface between High Velocity Oxygen Fuel (HVOF) spraying WC-Co coating and Q345C steel substrate. The results showed that the crack initiated at the coating surface, then propagated towards the substrate, and finally stopped at the interface. Cracks perpendicular to strain direction was formed in prior. Cross-linked cracks parallel to the axis direction were found to form after the saturation of the crack formation in the coating perpendicular to strain direction. The average shear strength varied from 132.6 to 200.3 MPa. The maximum shear strength obtained could be as high as 354.6 MPa and the minimum shear strength was 74.9 MPa. •Tensile test method was employed to investigate the interfacial adhesive strength of HVOF sprayed WC-Co coating.•The microstructural morphologies at different strain levels were observed to analyze the evolution of the cracks.•Shear strength between HVOF sprayed WC-Co coating and Q345C substrate was calculated by the modified A-R model.