The β phase evolution in Ti-6Al-4V additively manufactured by laser metal deposition due to cyclic phase transformations

Deformation and failure mechanisms of Ti–6Al–4V as built by selective laser melting

“…3b. Presence of β phase in as-printed microstucture has also been reported in the literature [15,20]. To verify the difference in hardness between the primary α′ and the surrounding substructure, we conducted 100 nanoindentations on a 20 by 20 µm 2 grid.…”

“…This orientation is pretty close to the maximum macroscopic shear stress if tensile loading normal to the build direction is applied. Existence of thin films of retained β phase at the interface between martensites has also been reported [15,20]. A lot of studies in the literature have focused on mechanical properties of selective laser melted Ti-6Al-4V [19,21,22].…”

Microstructural Evolution During Post Heat Treatment of the Ti-6al-4v Alloy Manufactured by Laser Powder Bed Fusion

“…Depending on the duration of exposure to high temperature, the distribution and the content of solute elements in the b phase can be different, which affects the mean lattice parameter of the phase. Previous studies have shown that the vanadium content in the b phase at different build heights may vary due to the different thermal cycles undergone by each deposited layer [54,55]. In our case, the EPMA analysis carried out on a sample manufactured vertically (0 ) showed a chemical homogeneity of main solute elements.…”

Design and Tailoring of Alloys for Additive Manufacturing

“…[103] Such grain refinement by solid-state thermal cycling of a eutectoid product (e.g., pearlite) has previously been reported in steels, for example. [104] Opportunities clearly exist to better match by alloy design the nucleation and growth of phases in the solid state to the thermal cycling conditions in AM, particularly in Ti alloys, [105,106] in addition to solid-state microstructural aspects like metastable phase decomposition. [13,98,99] For example, the role of thermal cycling in modifying the complex phase transformations in titanium aluminide intermetallic alloys during AM has recently been studied.…”