Structural and Mechanical Properties of Arc-Sprayed Ni–Cr Coating Post-Treated by Surface Mechanical Attrition Treatment (SMAT)

Abstract : This study focuses on the effects of a surface mechanical attrition treatment on the structural and mechanical behavior of arc-sprayed Ni–Cr coatings deposited on steel substrates. The surface of the as-sprayed and SMATed coatings was characterized by X-ray diffraction, Scanning Electron Microscopy, and non-contact profilometry. The coating porosity was evaluated by using image analysis software. The residual stresses were determined using X-ray diffraction with the sin2ψ. Indentation tests were carried out on the cross sections of the different coatings to evaluate their hardness. The wear properties of the coatings were assessed using a pin-on-disk tester at ambient temperature without lubrication. The results showed that surface mechanical attrition treatment (SMAT) induced a grain refinement on the coating surface due to severe plastic deformation, which was associated with a significant improvement of the mechanical properties.