Perspectives on Titanium Science and Technology

Effect of the build orientation on the mechanical properties and fracture modes of SLM Ti–6Al–4V

“…It is well known that poor ductility is the major limitation for additive manufactured α+β Ti alloys in as-built condition and thus the post processing stress relief heat treatment has proved to be beneficial for SLM Ti-6Al-4V. The difference in ductility between the stress relieved and as-built parts can be explained considering the plasticity of the α+β phases [30].…”

“…The analysis of the orientation of the α laths (Fig. 12d) indicates the fracture has occurred in none of the basal or prismatic planes that are instead generally associated with α cleavage fracture [30,40,51]. In addition, the reconstruction of the parent β phase shows that all these α laths have originated from one unique grain.…”

“…The main microstructural features, in particular, porosity, prior-β grain boundaries, existing phases, and crystallographic texture will be described as they have a great influence on the mechanical behaviour and crack propagation in Ti alloys [30,31]. As the samples showed the same microstructure (i.e.…”

“…The as-built samples consist entirely of αʹ phase and hence the plastic deformation is mainly restricted to the basal and prismatic slip systems, namely the 0002 1120 and 1010 1120 [30]. As the αʹ grains do not form colonies of laths sharing the same orientation, the effective slip length is confined to single grains.…”

“…Table 3 shows that the elastic modulus does not vary with the build orientation or in other words, that the orientation of the prior-β grains has no significant influence on the elastic moduli of the specimens. It has been reported that the α crystal anisotropy has a marked effect of on the elastic modulus of Ti-6Al-4V with a strong crystallographic texture [30].…”