Hydrogen‐Induced Improvement of the Cylindrical Drawing Properties of a Ti–22Al–25Nb Alloy

Abstract

As an important method for improving the plasticity of titanium alloys, the "hydrogen (H)-induced plasticization" mechanism has been widely studied. The present study comparatively investigates the high-temperature tensile properties, deformation mechanism, and cylindrical drawing properties of hydrogenated and non-hydrogenated Ti-22Al-25Nb alloys. The results indicate that the "H-induced plasticization" effect is the most obvious at 0.2 wt% hydrogenation. At 960 C, the elongation percentage of the 0H alloy is 109% and the elongation percentage of the 0.2H alloy is 202%. Through a cylindrical drawing test, it is found that after hydrogenation, the forming performance of the alloy improved significantly.

Effect of Hydrogen on Phase Transformation, Thermal Deformation Behavior, and Forming Limit of TC2 Alloy

“…The most common type is the two‐phase α + β alloy, which has a α + β → β phase transformation temperature of approximately 940 °C . The α phase alloy has a hexagonal close‐packed (HCP) crystal structure, and its predominant slip system is (0001) basal slip . The β phase has a body‐centered cubic (BCC) crystal structure with various slip systems and good plastic deformation properties .…”

“…TC2 alloy also has a high high‐temperature strength, high thermoforming temperature, and high die wear, which are not favorable for the cost. The thermal hydrogen treatment of titanium alloy has been proven by a large number of experiments to effectively reduce the high‐temperature deformation resistance, reduce the thermoforming temperature, and improve the plastic deformation capacity . Its mechanism is that the hydrogen atom can weaken the metal bonds of the alloy, making the slip deformation of the alloy easier, decreasing deformation resistance.…”

Microstructure and Mechanical Properties of Ti2AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder

“…With the rapid development of aeronautic and aerospace technology, orthorhombic Ti 2 AlNb‐based alloys have attracted substantial attention for their high strength‐to‐weight ratio, ductility, creep and high‐temperature oxidation resistance, fracture toughness, and workability . According to the lattice structure, Ti 2 AlNb‐based alloy is composed of β phase (body centered cubic, bcc, disordered structure), B2 phase (made of two simple cubic lattices shifted by 1/2 the cubic diagonal), O phase (orthorhombic, Cmcm system based on Ti 2 AlNb), and α 2 phase (hexagonal close‐packed, hcp, DO 19 structure based on Ti 3 Al) …”