Stress-induced phase transformation during superplastic deformation in two-phase Ti–Al–Fe alloy

Superplastic Property of the Ti–6Al–4V Alloy with Ultrafine‐Grained Heterogeneous Microstructure

“…[11,12] In addition, stress induced phase transformation such as preferred b precipitation has been reported to act as an additional stress accommodation mechanism at grain boundary. [13,14] Furthermore, quite recently, the present authors have mentioned that frequent occurrence of dynamic recrystallization (under discontinuous manner) during tensile deformation (at temperatures ranging from 700 to 900 C) of the Ti-64 alloy with an a 0 martensite starting microstructure strongly acted as an accommodation mechanism, thereby resulting in an excellent tensile ductility. [15] Motyka has also pointed out that globularization from the elongated-a-grained starting microstructure contributed to high temperature ductility of Ti alloy.…”

Deformation-induced ambient temperature α-to-β phase transition and nanocrystallization in (α + β) titanium alloy

“…Also, the application of the high stress concentration to the a phase adjacent to the interface significantly increase its Gibbs free energy by several hundreds Joule per mol. 13 The increase of Gibbs free energy and the enrichment of Nb may eventually cause a high order of lattice instability of the a phase adjacent to the interface and compel the a phase to b phase. In combination with Figs.…”

“…12,13 Considerable efforts have been devoted to exploring novel b-titanium alloys by addition of d-electron-rich elements such as Mo and Nb to stabilize b phase at low temperature. 12,14 In a or (a + b) titanium alloys, thus far, the transformed b phase from the a phase has not been found in most of the ambient temperature experiments, except a recent report showing a high pressure (>67 GPa)-induced a-to-b phase transition in an aged Ti-15Mo-3Nb-3Al-0.2Si alloy.…”

Dynamic Phase Transformation during Hot-Forging Process of a Powder Metallurgy α+β Titanium Alloy

“…For example, Koike et al 4) investigated the dynamic phase transformation in a Ti5.3Al1.4Fe (mass%) alloy under superplastic deformation and found that the ¡¼¢ transformation in the ¡+¢ phase region was significantly enhanced and the ¢ transus was reduced by approximate 70 K. Yang et al 5) also found that the tensile deformation could accelerate the ¡¼¢ transformation in the Ti6Al4V alloy. In addition, an enhanced ¢¼¡ 2 transformation was also reported in a titanium-based Ti 3 Al intermetallic compound.…”