The Effect of In Process Heat Treatment on the Mechanical Properties of Cold Spray Coatings

Abstract

Cold spray (CS) is an additive manufacturing process which has recently gained interest within research and select high-end production systems; however, one of the primary factors limiting the deployment of this process is the relatively poor mechanical properties of the coatings in the as-sprayed state as compared with bulk counterparts. Therefore, this paper details the mechanical performance of Al 6061 CS coatings heat treated using a novel focused IR device. The heat treatment of the coatings was performed in-process with the aim of improving the ductility and strength of the CSed coatings processed using nitrogen carrier gas. The mechanical properties of the heat treated samples were compared to a traditional annealing process and an as-sprayed sample by tensile testing dog bone samples. It was found that the rapid IR heat treatment process delivered advantages with regard to mechanical properties when compared to the untreated state showing an increase in the UTS of the coatings by 52% and an increase in the elongation at failure by 43%. This work demonstrates that rapid heat treatment can be carried out on a CS coating, allowing targeted improvement of mechanical properties over load-bearing components in a more time-effective way than traditional heat treatment techniques allow.