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

Wire arc spraying is a cost effective deposition technique which is widely used to protect pipelines and metallic structures against corrosion. Mechanical properties of wire arc spraying coatings are mainly based on their microstructural characteristics such as voids, pores, and splat boundaries. The coatings generally exhibit heterogeneous microstructures that results in complex mechanical properties. It is a challenging task to experimentally capture these properties due to the difficulties of fabrication of sub-sized free standing coating samples for mechanical testing. The objective of this investigation is to characterize the mechanical behavior of wire arc sprayed Zn-20Al alloy using an efficient micromechanical-computational scheme. The microstructural images taken by scanning electron microscopy (SEM) were imported to an object oriented finite element (OOF) scheme and distinguished into phases of various components and subsequently discretized into finite elements (FEs). To examine the validity of this technique, experimental studies such as Knoop hardness test and nano indentation were conducted on the coating samples. The obtained hardness values were used to calculate elastic modulus of the coating material using some analytical methods. Comparison of the experimental data with finite element analysis results was used to explain the microstructural basis of the mechanical characteristics of Zn-20Al coating.