Effects of Surface Roughness on Bonding Behavior of Cold Spray Ti6Al4V Coatings

In this study, a penitential additive manufacturing method - cold spray was used to deposit Ti6Al4V powders onto Ti6Al4V substrates with different surface roughness by using a high pressure cold spray system. The coating quality was good with limited porosity and without phase transition. Interface bonding behavior between coating and substrate was studied, which indicated that smoother substrate surface would increase the bonding strength. Bending test showed that all the coated samples started to delaminate before substrate failure and smoother surface samples could resist higher stress than the rougher surface samples.