Effect of Process Induced Residual Stresses on Fatigue Behavior of High Velocity Oxy-Fuel (HVOF) Coated Carbide-Steel System

Thermal spray is a common technique used to produce coatings that create surfaces for enhanced performance (Wear, Corrosion) of engineering components. In an effort to replace electroplated chrome coatings, thermally sprayed cemented carbide coatings (Cr₃C₂ NiCr, WC Co/CoCr) have been employed for protecting metallic aerospace components against wear and corrosion. High Velocity Oxy-Fuel (HVOF) processes result in coatings with dense microstructures and excellent bonding, thus providing the requisite wear and corrosion resistance.  However, the coatings contain a complex state of stress arising from processing and these stresses also extended to the coating substrate interface.   There is anecdotal evidence that the induced stresses can have positive or deleterious effect on coating – substrate fatigue behavior.

This paper systematically addresses this interplay between processing, stresses, and fatigue performance of this structurally integrated coating. The critical role of process induced residual stresses is highlighted along with demonstration of a pathway for controlled introduction of residual stresses during deposition. The implications of this work are significant as it provides a framework for not only process control but also for integration of design with materials and processes.