Characterization of Surface Erosion from High Speed Single Micrometer Impacts on Al-6061 T6

Damage models for high speed atmospheric aerosol particle impacts are necessary to link numerical and experimental studies on boundary layer transition and vehicle surface erosion for relevant flight conditions. We present findings of ongoing damage and surface characterization of high speed (0.2 to 0.9 km s^-1) micrometer-sized ferrous sulfate particle impacts onto Al-6061 surfaces. In this experiment, well controlled 1.8 µm and 6.2 µm monodisperse (single diameter) particles of ferrous sulfate are generated and then subsequently accelerated by a converging diverging nozzle with particle speeds measured by laser doppler velocimetry. Surface topography changes facilitated by individual particle impacts are characterized as a function of particle size, impact speed and impact angle. We observe that the dimensionless crater volume,normalized by the particle volume, scales with the specific kinetic energy, with a scaling exponent of 2.0.