Effect of recycled powder content on the structure and mechanical properties of Ti-6Al-4V alloy produced by direct energy deposition

• Published in: Journal of alloys and compounds 2022-02, Vol.893, p.162264, Article 162264
• Main Authors: Shalnova, Svetlana A., Kuzminova, Yulia O., Evlashin, Stanislav A., Klimova-Korsmik, Olga G., Vildanov, Artur M., Shibalova, Anastasia A., Turichin, Gleb A.
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Anisotropy; Annealing; Chemical analysis; Deposition; Direct energy deposition; Ductile fracture; Macrostructure; Mechanical properties; Mechanical tests; Microstructure; Powder reuse; Shipbuilding; Ti-6Al-4V alloy; Titanium base alloys
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.162264

•Ti-6Al-4V DED samples with different content of recycled powder demonstrated the stable chemical composition.•The tendency of decrease the α lath size with increase of recycled powder content in Ti-6Al-4V samples was determined.•The degradation of mechanical properties of annealed DED samples with increase of recycled powder content was not observed.•No difference in fracture surfaces with different contents of the used powder. [Display omitted] Direct energy deposition (DED) is a promising additive manufacturing technique in the area of aerospace, automotive, shipbuilding and medical industries. DED allows producing large-scale parts that imply the use of a significant amount of powders. Powder reuse is an important task that leads to a reduction in the cost of the final products. In this work, Ti-6Al-4V samples were fabricated by DED technique with a mixture of unused and recycled powders in the recycled powder content of 0%, 10%, 25%, and 50%. The results show that the morphology of the powder does not change significantly due to a low number of powder uses. Chemical analysis reveals a slight decrease of V in the recycled powder. The evolution of macrostructure with increasing recycled powder content was not revealed. In the as-built samples, the columnar prior β grains grow toward the build direction with a typical Widmanstätten structure consisting of the thin α' laths. The mix of Widmanstätten microstructure and basket weave microstructure appears after the annealing at 800 ℃. Furthermore, the horizontal and vertical annealed samples exhibit ductile fracture and inconspicuous anisotropy of tensile and impact mechanical properties.