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. 2025 Aug 21;15(1):30703.
doi: 10.1038/s41598-025-16282-0.

Microstructure and corrosion resistance of hybrid additively manufactured Ti-6Al-4V via laser powder bed fusion

Omer F Mohamed  1 , Linda Ismail  2 , Chandrabhan Verma  3 , Imad Barsoum  2   4 , Akram AlFantazi  3 , Andreas Schiffer  5   6
Affiliations

Microstructure and corrosion resistance of hybrid additively manufactured Ti-6Al-4V via laser powder bed fusion

Omer F Mohamed et al. Sci Rep. .

Abstract

Over the last decade, the Hybrid Additive Manufacturing (HAM) approach has been introduced to synergistically combine the design flexibility of Additive Manufacturing (AM) with the larger build volume and faster production rates offered by conventional manufacturing methods. In this work, Ti-6Al-4V powder was printed on the conventional machined Ti-6Al-4V substrate by laser powder bed fusion (LPBF), and the corrosion behavior was studied in 3.5 wt.% NaCl and 0.5 M H2SO4 solutions. The multi-material part's interface characteristics, microstructure, and microhardness properties were investigated. In addition, the corrosion behaviors of the LPBF, hybrid, and substrate Ti-6Al-4V parts were characterized, with subsequent analysis of the bimetallic structure's corroded surface morphology and composition. The corrosion behavior across all samples in each solution followed similar trends with minor variations. However, the hybrid component with strong and defect-free interfacial bonding demonstrates the feasibility of HAM in maintaining comparable corrosion performance to that of individual materials. Microstructural features of Ti-6Al-4V, including grain morphology, phase fraction, and oxide layer formation, tend to substantially influence corrosion resistance in saline and acidic environments.

Keywords: Acid/Alkaline/Neutral corrosion; Bimetal; Hybrid additive manufacturing; Interface characteristics; Multi-material; Titanium.

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Conflict of interest statement

Declarations. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
(a) Schematic of the multi-material Ti-6Al-4V part, (b) Photograph of the multi-material sample showing the LPBF, hybrid, and substrate regions.
Fig. 2
Fig. 2
XRD patterns of the LPBF and substrate Ti-6Al-4V parts.
Fig. 3
Fig. 3
OM images showing the microstructure of the Ti-6Al-4V multi-material part within three distinct regions (sectioned parallel to the build direction): (a) LPBF, (b) Substrate, (c) Hybrid.
Fig. 4
Fig. 4
SEM images showing the microstructure of the Ti-6Al-4V multi-material part within three distinct regions (sectioned parallel to the build direction): (a) LPBF, (b) Substrate, and (c) Hybrid (the dashed line represents the interface). Corresponding EDS maps of Ti (d), Al (e), and V (f) are also shown.
Fig. 5
Fig. 5
EBSD IPF maps showing the grain distribution and orientation of the Ti-6Al-4V multi-material sample.
Fig. 6
Fig. 6
(a) Comparison of surface roughness between the LPBF, hybrid, and substrate Ti-6Al-4V samples after polishing. (b) Microhardness measurements were taken within the LPBF, hybrid, and substrate regions of the hybrid Ti-6Al-4V part.
Fig. 7
Fig. 7
Tafel curves for the LPBF, hybrid, and substrate Ti-6Al-4V samples in (a) 3.5 wt.% NaCl (b) 0.5 M H2SO4.
Fig. 8
Fig. 8
Nyquist and Bode plots of the LPBF, hybrid, and substrate Ti-6Al-4V: (a)-(b) 3.5 wt.% NaCl, (c)-(d) 0.5 M H2SO4, (e) Fitting circuit.
Fig. 9
Fig. 9
SEM images of LPBF, Substrate, and Hybrid Ti-6Al-4V samples captured after the corrosion test (a)-(c) in 3.5 wt.% NaCl (Surface features include corrosion-induced attack sites and AM-related defects), (d)-(f) in 0.5 M H2SO4.
See this image and copyright information in PMC

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