Room-temperature tensile properties of float-zone processed ß-stabilized ?-TiAl(Nb,Cr,Zr) intermetallic

We extend the study of Ti-44Al-5Nb-3Cr-1.5Zr (at%) β-stabilized intermetallic processed by high-gradient (300 °C cm-1) induction float zone (FZ) technique that reported in Mater. Lett.162 (2016)180. The alloy ingots possess unique phase microstructure consisting of (y+α2) submicron-scaled strictly oriented lamellar matrix with incorporated minor y-granular fraction, and the least intergranular quota of β(Ti)/B2 phase. The tensile tests of axially-oriented bars have shown high average yield strength (YS) value of 837 MPa and ultimate strength (UTS) of 983 MPa along with the rupture elongation of 1.45%. Judging by these values, FZ-processing could be proposed as the efficient alternative to complex multistage thermal treatments or HIPing of cast β-stabilized intermetallics. Advanced room-temperature (RT) tensile deformability of alloy with specific microstructure and composition is explained by the softening of chromium-alloyed B2 intergranular fraction due to mutually exclusive redistribution of Cr and Zr between the conjugate y and B2 phases.