A Review—Additive Manufacturing of Intermetallic Alloys Based on Orthorhombic Titanium Aluminide Ti2AlNb

Abstract

Titanium alloys based on orthorhombic titanium aluminide Ti2AlNb are promising refractory materials for aircraft engine parts in the operating temperature range from 600–700 °C. Parts made of Ti2AlNb-based alloys by traditional technologies, such as casting and metal forming, have not yet found wide application due to the sensitivity of processability and mechanical properties in chemical composition and microstructure compared with commercial solid-solution-based titanium alloys. In the last three decades, metal additive manufacturing (MAM) has attracted the attention of scientists and engineers for the production of intermetallic alloys based on Ti2AlNb. This review summarizes the recent achievements in the production of O-phase-based Ti alloys using MAM, including the analysis of the feedstock materials, technological processes, machines, microstructure, phase composition and mechanical properties. Powder bed fusion (PBF) and direct energy deposition (DED) are the most widely employed MAM processes to produce O-phase alloys. MAM provides fully dense, fine-grained material with a superior combination of mechanical properties at room temperature. Further research on MAM for the production of critical parts made of Ti2AlNb-based alloys can be focused on a detailed study of the influence of post-processing and chemical composition on the formation of the structure and mechanical properties, including cyclic loading, fracture toughness, and creep resistance.

Influence of copper on the microstructure and mechanical properties of titanium ortho-alloy produced by selective laser melting

“…Интерметаллидные сплавы на базе алюминидов титана получили особое внимание со стороны исследователей как потенциальные жаропрочные материалы для замены никелевых сплавов, применяемых в автомобильной и аэрокосмической отраслях промышленности. Орторомбические титановые сплавы выделяют среди прочих благодаря их способности к жаростойкости и сопротивлению ползучести при повышенных температурах, обуславливаемой наличием орторомбического интерметаллида Ti 2 AlNb [1]. В то же время присутствие интерметаллидной фазы вызывает сложности при изготовлении изделий из этих сплавов традиционными методами [2][3][4].…”

Low-Cycle Fatigue Behaviour of Titanium-Aluminium-Based Intermetallic Alloys: A Short Review

“…The widely used TiAl binary phase diagram for alloys with compositions near TiAl is shown in Figure 1. Illarionov et al [4] elucidated that the β phase can be stabilised by using two categories of alloying elements, viz. β isomorphous elements such as vanadium, molybdenum, tantalum and niobium, and β eutectoid forming elements such as chromium, iron, manganese, nickel and silicon.…”

“…There exists the crystallographic orientation relationship of (111)║(0001) and [110]║ [112 0] with a semi-coherent lattice match when the 𝛾 -phase is precipitated out of the 𝛼 matrix [6][7][8]. Illarionov et al [4] elucidated that the β phase can be stabilised by using two categories of alloying elements, viz. β isomorphous elements such as vanadium, molybdenum, tantalum and niobium, and β eutectoid forming elements such as chromium, iron, manganese, nickel and silicon.…”

“…When enough contents of these elements are added to the TiAl alloys, the β phase becomes stable at room temperature. Subsequently, the β-phase acts as a ductile second phase due to its 12 independent slipping systems which can improve the deformation behaviour and arrest or hinder the growth of micro-cracks that form in the brittle major constituents, the α 2 and γ phases [4]. The Ti-Al phase diagram gives conventional titanium alloys, and more importantly, forms the basis of the recently developed, implemented and commercialised lightweight high-temperature titanium-aluminides.…”