The Effect of Rapid Heat Treatment Process On The Mechanical Properties of Cold Spray Coatings

This paper details the mechanical testing of Al 6061 cold spray coatings before and after a rapid heat treatment with a novel focused IR device. The focused IR device was used to heat treat the cold spray coatings in-process with the aim of improving ductility, substrate-coating bond strength, and reducing residual stresses. The treated samples were compared to a controlled annealing process which was carried out in a furnace after cold spray. The power output of the IR device was set to the maximum level of 220 W/cm² which was focused over a 10 mm diameter outlet area. The number of passes and traverse speed of the heat treatment process were varied in order to optimise the effect of the heat treatment. The mechanical properties of the coating were tested by tensile testing of dog bone samples and by performing pull off tests. Residual stresses were evaluated using strain measurement changes, before cold spray and after heat treatment. It was found that the rapid IR heat treatment process delivered advantages with regard to mechanical properties when compared to the untreated state.