A promising microstructure/deformability adjustment of β-stabilized γ-TiAl intermetallics

• High-gradient induction float zone re-solidification of cast γ-TiAl(Nb,Cr,Zr) alloy.
• Unique ordered phase microstructure engineering.
• Drastic enhancement of both ambient and high-temperature mechanical properties

Ti–44Al–5Nb–3Cr–1.5Zr (at%) β-stabilized intermetallic was synthesized by the electron beam casting and afterwards re-solidified by the high-gradient (300 °C cm−1) induction float zone (FZ) technique. FZ-processing led to the ordered microstructure creation consisting of volumetrically prevailing (γ+α2) lamellar colonies separated by minor seam-like γ-granular interlayers, and the least intergranular quota of β(Ti)/B2 phase. The optimum phase balance, submicron interlamellar spacing and strict alignment of lamellae along the thermal gradient were controlled by FZ-conditions. Unique microstructural adjustment enhances drastically the yield and ultimate strengths, Young's modulus and creep resistance. Thus the high-temperature limit of γ-TiAl(Nb,Cr,Zr) structural applicability could be expanded from 750–800 °C towards 900–950 °C.

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