FATIGUE BEHAVIOR OF NANO-CRYSTALLINE COLD SPRAY COATED SPECIMENS

Nanocrystalline cryomilled and micro Al7075 powdershave been deposited on Al5052 substrates by low pressure cold spray coating technique in order to study the effect of nanostructured coating on fatigue behaviour of the coated material. Microstructural characteristics of the coating and substrate and the fatigue behaviour of the coated structure have been surveyed through experimental tests. The powders size and shape distribution have been studied by scanning electron microscopy. Grain size measurement is performed by X-ray diffraction using a single peak analysis. In order to obtain the fatigue S-N diagram, as-received and coated specimens with different treatment parameters have been fatigue tested at load control condition. X-ray diffraction has been used also to measure the residual stress distribution both in the deposited material and the substrate.