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

• Published in: Materials letters 2016-01, Vol.162, p.180-184
• Main Authors: Kartavykh, A.V., Asnis, E.A., Piskun, N.V., Statkevich, I.I., Gorshenkov, M.V., Korotitskiy, A.V.
• Format: Article
• Language: English
• Subjects: Adjustment; Balancing; Deformation and fracture; Intermetallic alloys and compounds; Intermetallics; Microstructure; Optimization; Phase transformation; Quotas; Solidification; Structural; Titanium aluminides; Ultimate tensile strength; Yield strength
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2015.09.139

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°Ccm−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. [Display omitted] •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