Process-structure-property considerations for wire-based directed energy deposition of Ti-6Al-4V

• Published in: Materials characterization 2023-11, Vol.205, p.113280, Article 113280
• Main Authors: Sims, Hannah, Pegues, Jonathan, Whetten, Shaun, Kustas, Andrew B., Moore, David
• Format: Article
• Language: English
• Subjects: Electron beam additive manufacturing; MATERIALS SCIENCE; Mechanical properties; Microstructural evolution; Titanium; Wire arc additive manufacturing (WAAM)
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2023.113280

Directed energy deposition (DED) is an attractive additive manufacturing (AM) process for large structural components. The rapid solidification and layer-by-layer process associated with DED results in non-ideal microstructures, such as large grains with strong crystallographic textures. These non-ideal microstructures can lead to severe anisotropy in the mechanical properties. Despite these challenges, DED has been identified as a potential solution for the manufacturing of near net shape Ti-6Al-4V preforms, replacing lost casting and forging capabilities. Two popular wire-based directed energy deposition (W-DED) processes were considered for the manufacturing of Ti-6Al-4V with assessments on their respective metallurgical and mechanical properties, as compared to a conventionally processed material. The two W-DED processes explored were wire arc additive manufacturing (WAAM) and electron beam additive manufacturing (EBAM). High throughput inspection and tensile testing procedures were utilized to generate statistically relevant data sets related to each process and sample orientation. The 2 AM technologies produced material with remarkably different microstructures and mechanical properties. Results revealed key differences in strength and ductility for the two disparate processes which were found to be related to differences in the metallurgical properties. [Display omitted] •W-DED processes result in high density, comparable to conventionally processed Ti-6Al-4V.•Strength and ductility are primarily influenced by the cooling rate and initial feedstock chemistry.•Grain boundary alpha contributes to significant anisotropy in ductility of W-DED Ti-6Al-4V.•Micro-texture leads to significant anisotropy in strength of EBAM processed Ti-6Al-4V.