Gas Gun Flyer Plate Impact Testing of Stainless Steel Deposited by Low Pressure Plasma Spraying and Cold Gas Dynamic Spraying

Understanding shock wave propagation behavior in coatings is valuable for predicting their performance in high-velocity impacts. Samples of stainless steel were deposited by low pressure plasma spray and cold gas dynamic spraying. The sound speeds of the deposits were measured, and the deposits were tested in flyer plate impact tests in a gas gun to determine the shock propagation and porosity compaction properties. The most porous sample was tested to determine its equation of state, while the other samples were tested to measure shock wave profiles as a function of deposition parameters. Comparison of the results between the coatings and to reference wrought stainless steel shows the effect of deposition conditions on the dynamic behavior of the deposits. Higher deposit density leads to higher sound speed. The shock speed for the highest porosity plasma sprayed deposit was below that of wrought stainless steel. The Hugoniot elastic limit stress for cold sprayed deposits is higher than that for plasma sprayed deposits due to the higher degree of cold work. Porosity crush up times were found to vary with the total porosity of the deposit. Better understanding of the behavior of these deposits under extreme impact conditions is demonstrated.