Application of selective laser melting (SLM) for hybrid aerospace structures

The study investigates the adhesion properties of SLM manufactured Titanium (Ti-6Al-4V) alloy surfaces for metal-metal and metal-composite hybrid joints using Mode I Double Cantilever Beam (DCB) specimens. The results indicate that the inherent micro-topology of the SLM surface is able to maximise the bonding potential of the adhesive. With the introduction of additional macro-surface features, the crack path is deflected from a straight mode I path and follows the design of the surface features. Selected macro-features were found to increase the fracture toughness by up to 50%. Finite element analysis indicates that the rise in fracture toughness is due to two factors: 1) the increase in the effective crack path length and 2) a shift from mode I to mode II crack growth.