PRODUCTION AND CHARACTERIZATION OF CELLULAR Ti6Al4V ALLOYS BY ADDITIVE MANUFACTURING FOR BALLISTIC APPLICATIONS

Date

2025-11-27

Author

BÜYÜKHERGÜL, Ertuğrul

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In this study, gyroid and diamond cellular Ti-6Al-4V alloy structures with fully open, 50% open, and closed-cell morphologies were manufactured by the Electron Beam Melting (EBM) technique for ballistic applications. Structural characterization was complemented by quasi-static compression and drop-weight impact tests applied to all cellular configurations. In addition, the deformation behavior of fully open gyroid and diamond structures under impact loading was comparatively investigated by Finite Element Analysis (FEA) within the elastic regime. Microstructural examinations of the cell walls revealed pronounced anisotropy associated with the EBM process. Elongated prior-β grains aligned parallel to the build direction containing columnar α and β phases were observed. Quasi-static compression tests produced stress–strain responses typical of elastic–plastic foams, characterized by an initial linear elastic region, a plateau region following a sudden stress drop, and a densification stage where the flow stress increases rapidly. Among the fully open cellular structures, the diamond geometry exhibited higher elastic modulus, compressive strength, and toughness. Diamond structure has efficient load transfer capability under impact loading, which generated smaller craters demonstrating superior energy absorption performance. When cellular morphologies were compared, closed-cell diamond structures showed the best quasi-static mechanical properties relative to fully open and 50% open diamond counterparts. However, the 50% open diamond structures displayed enhanced energy absorption by dissipating impact energy within their open porous regions. FEA results showed that the fully open diamond structure exhibited approximately 65% lower maximum deformation, while the gyroid developed higher shear stresses and about 20% greater equivalent strain values.

Subject Keywords

Ti-6Al-4V, Electron Beam Melting, Cellular Structures, Ballistic Protection, Impact Loading

URI

https://hdl.handle.net/11511/118321

Collections

Graduate School of Natural and Applied Sciences, Thesis