Deformation mechanisms and slip transfer in a Ti44Al2Mo alloy

Characterization of the high temperature deformation behavior of two intermetallic TiAl–Mo alloys

“…A closer analysis of the grain morphology and grain sizes proves that both phases (β o þ γ) participate in deformation, although for both alloys at 1150°C, 1200°C and for the Ti-45Al-3Mo alloy up to 1250°C the β o -phase is ordered. Morris et al [6] also found that in a Ti-44Al-2Mo alloy both, the β o -and the γ-phase, show deformability at elevated temperatures. By means of SEM and transmission electron microscopy (TEM) the authors could show that the γ-TiAl phase was deformed by ordinary 1/2 o110] dislocations and mechanical twinning along 1/6 o112].…”

“…Then ordinary o 100 4 dislocations and o111 4 superdislocations on {110} planes are activated in the β ophase by compression [6].…”

“…It is therefore necessary to study the material's behavior at high temperature deformation to design an economic manufacturing process with optimized forming parameters. Many research groups have investigated the deformation behavior of γ-TiAl based alloys consisting of three phases α/α 2 (α: A3 structure, α 2 : D0 19 structure), β/β o (β: A2 structure, β o : B2 structure) and γ (L1 0 structure) or consisting of two phases α/α 2 and γ as reported in [4][5][6][7][8][9][10][11][12][13][14] amongst others. Up to now, in the literature only limited information can be found about the hot-deformation behavior of alloys containing high amounts of β/β o -phase.…”

Plasticity and brittleness of the ordered βo phase in a TNM-TiAl alloy

“…On the other hand, Morris et al [5,6] investigated the RT mechanical properties of a Ti-44Al-2Mo (at%) alloy which shows that plastic elongation (0.5%) was higher in the as-HIPed condition with a higher o phase volume fraction (15%), compared to the other process conditions. Besides, these authors observed two types of dislocations in the o grains: <100> dislocations and dissociated <111> superlattice dislocations, which formed pile-ups nucleated at grain boundaries under the effect of deformation in adjacent grains.…”

Structure and Properties of Ti-Al-Ta and Ti-Al-Cr Cladding Layers Fabricated on Titanium

“…The issues concerning the formation of ω-related phases in TiAl-based alloys with β-stabilizers are widely discussed in the literature. Precipitations of ω-related phases in the β/B2 matrix were found in alloys with additions of niobium [29,32,33,57], in the 4Zr-4Nb alloy [58], in alloys with Mo [59], V [60], Cr [61], etc. Shao and Tsakiropoulos [62] analyzed the stability of ω phase in Ti-Al-X alloys as a function of the aluminum content and the type of transition element added to the alloy.…”