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<p>The present study provides the first systematic investigation of Fe addition (1.7–7.5 wt%) in Ti4Al3V alloy fabricated by WEBAM, focusing on constitutional supercooling-induced grain refinement, β-phase stabilization, and isothermal ω-phase precipitation. Achieving refined equiaxed prior β-Ti microstructures in titanium alloys via electron beam additive manufacturing remains challenging due to epitaxial grain growth under slow cooling, which results in columnar grain growth. Alloying with β-stabilizing elements such as Fe offers a promising route to overcome this limitation by promoting constitutional supercooling and limiting the epitaxial grain growth mechanism. In this paper, the structural and phase evolution of Ti4Al3V-Fe alloys containing 1.7, 2.5, and 7.5 wt% Fe and produced by dual-wire electron beam additive manufacturing (WEBAM) has been investigated. The addition of 1.7 to 2.5 wt% Fe resulted in the refinement of prior β-Ti grains with a simultaneous reduction of their aspect ratio as well as the formation of α/β(Fe) lath structures. Ultimate tensile strength and yield stress improved to 785&#xa0;MPa and 725&#xa0;MPa on adding 1.7 wt% Fe. Ti4Al3V-2.5 wt% Fe alloy possessed even higher ultimate tensile strength and yield stress values, i.e., 1064&#xa0;MPa and 990&#xa0;MPa, respectively. The addition of 7.5 wt% β-supporting Fe allowed the formation of structures with 81 vol% β(Fe)-Ti and elliptical ω-Ti precipitates with grain boundary fine lath α-Ti. The Ti4Al3V-7.5 wt% Fe alloy exhibited higher hardness compared to that of the as-built Ti4Al3V and was characterized by brittle fracture in tensile testing as a result of ω-embrittlement.</p> Graphical Abstract <p></p>

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Microstructure and Strength Evolution in Ti4Al3V-xFe Alloys Obtained by Dual-Wire Electron Beam Additive Manufacturing

  • 期刊论文

  • 发表日期：

    2025年11月22日

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  • Aleksandra Nikolaeva,
  • Anna Zykova,
  • Andrey Vorontsov,
  • Aleksander Panfilov,
  • Evgenii Kuzminov,
  • Denis Gurianov,
  • Angelina Gusarenko,
  • Nickolai Savchenko,
  • Evgeny Kolubaev,
  • Sergei Tarasov

摘要

The present study provides the first systematic investigation of Fe addition (1.7–7.5 wt%) in Ti4Al3V alloy fabricated by WEBAM, focusing on constitutional supercooling-induced grain refinement, β-phase stabilization, and isothermal ω-phase precipitation. Achieving refined equiaxed prior β-Ti microstructures in titanium alloys via electron beam additive manufacturing remains challenging due to epitaxial grain growth under slow cooling, which results in columnar grain growth. Alloying with β-stabilizing elements such as Fe offers a promising route to overcome this limitation by promoting constitutional supercooling and limiting the epitaxial grain growth mechanism. In this paper, the structural and phase evolution of Ti4Al3V-Fe alloys containing 1.7, 2.5, and 7.5 wt% Fe and produced by dual-wire electron beam additive manufacturing (WEBAM) has been investigated. The addition of 1.7 to 2.5 wt% Fe resulted in the refinement of prior β-Ti grains with a simultaneous reduction of their aspect ratio as well as the formation of α/β(Fe) lath structures. Ultimate tensile strength and yield stress improved to 785 MPa and 725 MPa on adding 1.7 wt% Fe. Ti4Al3V-2.5 wt% Fe alloy possessed even higher ultimate tensile strength and yield stress values, i.e., 1064 MPa and 990 MPa, respectively. The addition of 7.5 wt% β-supporting Fe allowed the formation of structures with 81 vol% β(Fe)-Ti and elliptical ω-Ti precipitates with grain boundary fine lath α-Ti. The Ti4Al3V-7.5 wt% Fe alloy exhibited higher hardness compared to that of the as-built Ti4Al3V and was characterized by brittle fracture in tensile testing as a result of ω-embrittlement.

Graphical Abstract