Hydrogen influence on defect structure and mechanical properties of EBM Ti-6Al-4V

The Effects of Hot Isostatic Pressing (HIP) and Heat Treatment on the Microstructure and Mechanical Behavior of Electron Beam-Melted (EBM) Ti–6Al–4V Alloy and Its Susceptibility to Hydrogen

“…The average density of the non-hydrogenated alloy in the as-built, HIP, and HT conditions was 4.415 ± 0.003 (99.59%), 4.422 ± 0.002 (99.75%), and 4.416 ± 0.002 (99.62%) g/cm 3 , respectively, while the theoretical density was 4.4328 g/cm 3 [ 22 , 26 , 27 , 42 ]. This indicates a slight density improvement for the HIP alloy.…”

“…The reaction of hydrogen with matrix elements can form hydride phases such as δ (fcc), γ (fct, c / a > 1), and ε (fct, c / a < 1) [ 26 , 27 , 28 , 29 , 33 , 34 , 35 , 36 , 37 ]. Several studies were conducted to explore the effect of the typical microstructures of AM Ti–6Al–4V on its sensitivity to HE [ 19 , 28 , 29 , 36 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. Navi et al [ 41 ] investigated the influence of EC on both EBM and wrought Ti–6Al–4V alloys with a similar β-phase contents.…”

Hydrogen Embrittlement of Ti-Al6-V4 Alloy Manufactured by Laser Powder Bed Fusion Induced by Electrochemical Charging

“…This level of depth approximately corresponds with the depth of the visually affected layer observed in optical micrographs (~110 µm, Figure 5h,i), as well as the depth in which hydrides dominate (Figure 3c). The observed hardness increase can be related to the growth of internal stresses in the material due to the dissolution of hydrogen in the α and β solid solutions and distortion of the crystal lattice by formation of hydrides [10,35]. The as-built 3D printed sample behaved in the opposite manner (Figure 7a), but the hardness profile can also be accurately related to the microstructural changes.…”

“…Not many studies describing the effect of hydrogen penetration on the mechanical properties of Ti-Al6-V4 alloy manufactured additively are currently available. There are several studies [10][11][12][13][14] dealing with hydrogen trapping in Ti-Al6-V4 alloy prepared via Electron Beam Powder Bed Fusion of Metals (PBF-EB/M), another additive manufacturing technology belonging in the same technological group of powder-bed technologies as PBF-LB/M. However, PBF-EB/M yields a material with a different microstructure than PBF-LB/M due to the use of an electron beam, vacuum, and different fabrication strategy, and thus a different thermal history experienced by the material.…”