High strain-rate deformation of laser powder bed fused Ti5553 alloy

This study investigates the dynamic impact loading behavior of laser powder bed fused (LPBF) Ti-5Al-5 V-5Mo-3Cr (Ti5553) alloy using a Split Hopkinson Pressure Bar (SHPB) system at strain rates of 900–2150 s−1. Microstructural characterization by OM, SEM, XRD, and EBSD was performed to assess the grain morphology, crystallographic texture, and deformation mechanisms. Results revealed a strain-rate-dependent increase in the yield strength, ultimate compressive strength (UCS), and ductility, attributed to strain-rate hardening, grain refinement, thermal softening, and a texture transition toward the 〈110〉 orientation. The UCS increased from 1230 MPa to 1385 MPa (12.6 %) as the strain rate rose from 900 s−1 to 2150 s−1, while strain rose from 0.075 to 0.196, indicating enhanced ductility and impact resistance. EBSD revealed progressive lattice distortion and dislocation accumulation with increasing strain rate. Macro and micro texture analyses showed a transition from a solidification-driven 〈001〉 texture to a strain-induced 〈110〉 orientation, suggesting that slip along {110}〈111〉 systems can be a major deformation mechanism. No adiabatic shear banding was detected, confirming thermal and microstructural stability under dynamic impact loading under the tested conditions. These findings provide new insights into the high strain-rate response of LPBF-Ti5553 and support its potential for demanding aerospace and structural applications.