Dynamic fracture behavior of selective laser melted Ti6Al4V alloy under three-point bending test

The dynamic fracture behavior of Ti6Al4V ELI (Grade 23) specimens fabricated by Selective Laser Melting (SLM) was examined using an instrumented drop tower system. The specimens, cut from a rectangular plate, were tested in their as-built condition. To characterize their mechanical performance, initial tensile tests were carried out along both the build and scan directions. Mechanical property measurements indicated that the scanning direction exhibited slightly higher values of yield strength, ultimate tensile strength, and elongation at break compared to the build direction. Subsequent to the tensile tests, dynamic three-point bending experiments were conducted at varying impact velocities. These tests enabled the determination of both initiation and propagation to fracture toughness values under different loading rates in both directions. The results demonstrated that fracture toughness values—both at initiation and during crack propagation increased with higher loading rates. Furthermore, fracture toughness values obtained in the build direction were consistently lower than those measured in the scanning direction, revealing a novel link between directional anisotropy and rate-dependent fracture behavior.