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Materials Science and Engineering of Powder Metallurgy >

2025 , Vol. 30 >Issue 3: 204 - 214

DOI: https://doi.org/10.19976/j.cnki.43-1448/TF.2025002

Engineering and Technology

Effects of Nb content on microstructure and mechanical properties of Ti-Al-Nb alloys fabricated by laser-directed energy deposition

  • YUAN Xiaohui ,
  • LI Ruidi ,
  • YUAN Tiechui
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  • 1. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China;
    2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China

Received date: 2025-01-17

  Revised date: 2025-05-06

  Online published: 2025-07-28

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Abstract

The microstructure of the Ti-Al alloys fabricated by laser-directed energy deposition (LDED) often exhibits coarse columnar grains through several melten pools, which makes it difficult to obtain uniform mechanical properties. In this paper, Nb was selected as an additive element of Ti-Al binary alloys, and a series of Ti-6Al-xNb (x=5, 6.5, 7.5; mass fraction) ternary alloys were fabricated by LDED. The microstructure, room temperature tensile properties, and deformation mechanism of the alloys were characterized by optical microscope, X-ray diffractometer, scanning electron microscope, and electron backscattering diffractometer. The effects of Nb content on the microstructure and tensile properties of LDED Ti alloys were investigated. The results show that the microstructures of the alloys with different Nb contents are similar, which are mainly composed of elongated acicular or lamellar α/α′ phase, and there are a small amount of residual β phase. The alloy has the highest ultimate tensile strength ((902±35) MPa) and yield strength ((849±20) MPa) when the mass fraction of Nb is 6.5%, which is mainly attributed to the reduction in grain size. In addition, the elongation of these alloys decrease gradually with increasing Nb content. The lowest elongation of (10.2±1.4)% can be observed when the mass fraction of Nb is 7.5%.

Key words： Ti-Al-Nb alloy; laser-directed energy deposition; microstructure; mechanical property; deformation mechanism

Cite this article

YUAN Xiaohui , LI Ruidi , YUAN Tiechui . Effects of Nb content on microstructure and mechanical properties of Ti-Al-Nb alloys fabricated by laser-directed energy deposition[J]. Materials Science and Engineering of Powder Metallurgy, 2025 , 30(3) : 204 -214 . DOI: 10.19976/j.cnki.43-1448/TF.2025002

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