Researchers from Trinity College Dublin reported on the results of mechanical testing of Al 6061 cold spray coatings before and after a rapid heat treatment with a novel focused IR device, at the ITSC 2019 conference sponsored by the Thermal Spray Society of ASM International.
The focused IR device was used to heat treat the cold spray coatings in-process, with the aim of improving ductility, increasing substrate/coating bond strength, and reducing residual stresses. The treated samples were compared to samples subjected to a controlled annealing process that 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 the traverse speed of the heat treatment process were varied in order to optimize the effect of the heat treatment. The mechanical properties of the coating were tested by tensile testing of dog-bone samples and by 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. (Photo shows SEM image of fracture surface of cold-sprayed aluminum 6061.)
Title: The Effect of Rapid Heat Treatment Process on the Mechanical Properties of Cold Spray Coatings
Authors: Richard Jenkins, Dr. Barry Aldwell, Jonathan Cassidy, Prof. Rocco Lupoi, Trinity College Dublin
