Mechanical and precorroded fatigue properties of coated aluminium aircraft skin system as function of various thermal spray processes

Aluminium coatings deposited on AA2024-T3 by the flame arc, atmospheric plasma and high velocity oxyfuel (HVOF) processes were evaluated using quantitative metallography, microhardness, adhesion, three point bend and conventional fatigue tests as well as fatigue tests on precorroded samples. Comparison of the microstructures, mechanical properties, and the fatigue and precorroded fatigue properties of samples with the three types of thermal spray coating, as well as samples of bare AA2024-T3 and Alclad AA2024-T3, revealed that HVOF is the most promising thermal spray process for the deposition of aluminium coatings, and, in particular, HVOF coatings greatly increase the fatigue and precorroded fatigue lifetimes of the AA2024-T3 substrate.