Investigation on Relationship Between Microstructural Characteristics and Mechanical Properties of Wire-Arc-Sprayed Zn-Al Coating

Wire arc spraying is a cost-effective thermal spraying technology to deposit a protective coating layer on the surface of industrial components. Mechanical properties of wire arc spraying coatings are mainly influenced by their heterogeneous microstructure, resulting in complex and anisotropic mechanical properties. The objective of this investigation is to characterize the mechanical behavior of wire-arc-sprayed Zn-15Al alloy using an efficient micromechanical-computational scheme. Scanning electron microscopy images were imported to an object-oriented finite element scheme and distinguished into various phases, and then subsequently discretized into finite elements. To examine the validity of this technique, experimental studies, such as Knoop and Vickers microhardness, resonance frequency, and nanoindentation, were conducted on the freestanding coating samples. The elastic modulus of the coating was also calculated using well-known analytical methods. Comparison of the results obtained in this study was used to investigate the relationship between the microstructural features and mechanical properties in coating materials. Image-based finite element analysis showed good agreement with the experimental measurements and proved the effect of splat boundaries on the reduction in mechanical strength between coating layers and, consequently, lower elastic modulus of the wire-arc-sprayed Zn-15Al coating in the longitudinal direction compared to the transversal one.