Developing ductile and isotropic Ti alloy with tailored composition for laser powder bed fusion
Wang, Leyun; Song, Zhe; Zhang, Xuan; Park, Jun-Sang; Almer, Jonathan; Zhu, Gaoming; Chen, Yiwen; Li, Quan; Zeng, Xiaoqin; Li, Yanjun
Peer reviewed, Journal article
Published version
Permanent lenke
https://hdl.handle.net/11250/3055226Utgivelsesdato
2022Metadata
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- Institutt for materialteknologi [2563]
- Publikasjoner fra CRIStin - NTNU [38685]
Sammendrag
Laser powder bed fusion (LPBF) is an advanced technology to create metallic components with complex geometry. Ti-6Al-4V (Ti64) is one of the most frequently used materials for LPBF. The intrinsic high cooling rates and ultra-high directional thermal gradient of melt, however, lead to a hierarchical structure composed of fine martensitic α' within columnar prior-β grains in LPBF Ti64. This microstructure results in poor ductility and strong mechanical anisotropy in as-built Ti64 components, which largely limit their applications. Here, we report that the above shortcomings can be overcome by tailoring the alloy composition. Specifically, by reducing the aluminum content from 6 wt% to 4 wt%, the resultant LPBF Ti-4Al-4V (Ti44) alloy exhibits substantially improved ductility and mechanical isotropy. These improvements are attributed to grain refinement during solidification and the activation of multiple slip modes and twinning in the as-built material during deformation. This work offers a simple strategy to design new titanium alloys for LPBF with significantly improved ductility and isotropy.