Fabrication of Ti-Alloy Powder/Solid Composite with Uniaxial Anisotropy by Introducing Unidirectional Honeycomb Structure via Electron Beam Powder Bed Fusion

Abstract

In this study, a Ti–6Al–4V alloy composite with uniaxial anisotropy and a hierarchical structure is fabricated using electron beam powder bed fusion, one of the additive manufacturing techniques that enable arbitrary fabrication, and subsequent heat treatment. The uniaxial anisotropic deformation behavior and mechanical properties such as Young’s modulus are obtained by introducing a unidirectional honeycomb structure. The main feature of this structure is that the unmelted powder retained in the pores of the honeycomb structure. After appropriate heat treatment at 1020 °C, necks are formed between the powder particles and between the powder particles and the honeycomb wall, enabling a stress transmission through the necks when the composite is loaded. This means that the powder part has been mechanically functionalized by the neck formation. As a result, a plateau region appears in the stress–strain curve. The stress transfer among the powder particles leads to the cooperative deformation of the composites, contributing to the excellent energy absorption capacity. Therefore, it is expected that the composite can be applied to bone plates on uniaxially oriented microstructures such as long bones owing to its excellent energy absorption capacity and low elasticity to unidirectionally suppress stress shielding.

Review — Research and Development of Titanium-Containing Biomedical High Entropy Alloys (BioHEAs) Utilizing Rapid Solidification via Laser-Powder Bed Fusion

“…The L-PBF method can produce the desired shape with high accuracy. 28,29) Furthermore, it is possible to control the material properties for each location. Living bones are the targets of implanting a biological metal material.…”

Review—Metal Additive Manufacturing of Titanium Alloys for Control of Hard Tissue Compatibility

“…The authors have developed bone medical devices that can induce bone functionalization based on the anisotropic microstructure peculiar to living bone by using metal additive manufacturing technology. 4,25,26)…”

Effect of Cooling Rate on Powder Characteristics and Microstructural Evolution of Gas Atomized β-Solidifying γ-TiAl Alloy Powder

“…4,5) Thus, powder metallurgy has raised interest because of its comparative advantages, which promise a more fine and homogeneous microstructure, reducing the unnecessary additional processing through near-net shape, and enhancement of the mechanical properties by establishing peculiar microstructure such as additive manufacturing (AM) process. [5][6][7][8][9][10][11] Gas-atomization is a widely adopted manufacturing process for the production of various metallic powders. [12][13][14] Although the gas-atomization process demands more cost investment, it yields much better spherical particles.…”