Effect of heat treatment on the microstructure and mechanical properties of 7075 aluminum alloy cold-spray coatings

Cold Spray (CS) exhibit unique features due to the low temperatures involved. However, the CS coating are harder than the corresponding powders and bulk alloys, which results in a low toughness and then greatly limits the application of CS. To overcome this shortage, preheat treatment of powder and post-heat treatment of CS coating are applied to improve the performance of cold-sprayed 7075 aluminum alloy coatings in this work. With increasing temperatures of post-heat treatment, the tensile strength of the coatings increased from 228 MPa to 309 MPa with elongation of 2.46%. Microstructure analysis of the heat-treated coatings revealed that the improvement in mechanical properties was primarily due to an increase in the secondary phase. Accordingly, 7075 aluminum alloy powder was preheat treated at 200 & DEG;C and then used for cold spraying, which resulted in improved mechanical properties in the resultant coatings exhibiting a tensile strength of 302 MPa and an elongation of 3.87%. These findings provide valuable insights into the practical application of cold-spraying technology in the aviation field.