Fatigue behaviour of fastener holes in high‐strength aluminium plates repaired by cold spray deposition

Abstract

AbstractThis work examines the fatigue behaviour of additive cold spray (CS) repairs of AA7075 and AA2024 fastener holes. Structural ring repairs around fastener holes were made by machining blend‐outs ranging from 1/8 to 1/2 the thickness of the plate, then refilling the section of removed material with CS deposition. The repairs were then tested in a lap shear geometry with the repair on both the free (outside) and the mating (inside) surfaces, as well as in remote uniaxial tension. CS repairs for the inside lap shear AA7075 repair configuration and the outside lap shear AA2024 repair configuration were found to have significantly increased fatigue lives even exceeding the number of cycles to failure of the undamaged, unrepaired control plates. Further, none of the CS repairs caused any detrimental impact on fatigue life, and microhardness results indicate that no thermal damage to the substrate occurred. Some interface cracking was seen in the CS repairs; however, no separation of the repair from the substrate was observed.