Adhesion properties of plasma transferred wire arc low-carbon steel coating sprayed on diecast aluminum alloys: Experiment and simulation

Abstract

This study examines the adhesion properties of plasma transferred wire arc (PTWA) coating of low-carbon steel deposited on two diecast flat aluminum alloy (A319 and A356) substrate materials. Experimental adhesion tests were performed according to ASTM C633 standards for three types of samples of varying interface patterns and/or substrate material. Finite element method (FEM) simulations were implemented to compare adhesion results with experimental observations, as well as analyze the separation and stress distribution. FEM simulations account for the portion of adhesion attributed to solely mechanical interlocking, whereas the experimental results rely on the adhesion at the interface due to mechanical interlocking and potential metallurgical bonding. Experimental results show that differences between the two interface patterns (dovetail and wave), and substrate materials (A319 and A356), will result in varying degrees of adhesion failure at the interface and cohesion failure within the coating. The studied dovetail pattern produces higher average normalized pull strength (0.87) compared to the corresponding wave pattern (0.64) of the same materials. The wave pattern on the A356 substrate had a slightly higher average normalized pull strength (0.75). While the dovetail pattern produced higher bond strength, it was found that mechanical interlocking was notably more successful in the wave pattern and the stress experienced by the coating and substrate was more uniformly distributed. As a result, the wave pattern is a prime candidate for further consideration and development.