A comprehensive comparison of dynamic strain localisation and mechanical behaviour in traditional and additively manufactured Ti6Al4V

Titanium alloys are widely used in aerospace, defence, automotive, and biomedical engineering owing to their high specific strength and excellent corrosion resistance. Additive manufacturing has emerged as a promising alternative to conventional production methods, offering the capability to fabricate complex geometries while reducing processing time and material waste. In this study, the high strain rate deformation behaviour of Ti6Al4V produced by selective laser melting is investigated using a Split Hopkinson Tension Bar system equipped with a multi-camera high-speed imaging setup. A comprehensive experimental programme is conducted on specimens manufactured in three different build orientations to assess the influence of processing direction on dynamic strain localisation and true stress–strain response. The post-necking behaviour is examined and compared with that of conventionally forged Ti6Al4V, revealing notable differences in ductility and strain localisation mechanisms. In addition, the high strain rate compressive behaviour of both material variants and their temperature dependence are investigated using a Split Hopkinson Compression Bar system equipped with thermal conditioning. The deformation and failure mechanisms of additively manufactured specimens produced in different orientations are further examined through post-mortem analysis of the fracture surfaces. • The dynamic behaviour and strain localisation of forged and SLM Ti6Al4V are compared. • The additive manufacturing process introduces significant anisotropy in the material. • A high-rate testing method incorporating dual high-speed imaging is presented. • The strain rate and temperature dependencies of both alloys are examined in detail. • The lower ductility of SLM Ti6Al4V must be considered in safety-critical component design.