Microstructure and creep strength of fully-lamellar TiAl alloys containing beta-phase

Microstructural instability and embrittlement behaviour of an Al-lean, high-Nb γ-TiAl-based alloy subjected to a long-term thermal exposure in air

“…No matter how slowly the B2(u) forms, the widespread formation of B2(u) from thin a 2 þ g lamellae and from coarse single a 2 laths is somewhat surprising in terms of the extent, size and volume fraction of the formation. Isolated precipitation of b/B2(u) fine particles during a thermal process was reported in low-Nbcontaining, Fe þ V containing and W containing TiAl alloys [42][43][44][45][46][47]. However, in the high-Nb-containing TiAl alloy, the formation of micron-sized B2(u) grains both from a 2 laths only and from thin a 2 and g lamellae is found to be a universal phenomenon during the 10,000-h thermal exposure, producing about 9 vol.% of ordered phases B2(u) and distributing in every places where a 2 lamellae exist.…”

Correlation of high temperature oxidation with tensile properties for Ti–48Al–2Cr–2Nb and Ti–48Al–2Cr–2Fe alloys

“…Regarding the alloying effects for 2Cr2Nb and 2Cr2Fe, Cr addition is most effective to improve the ductility [11,12], Nb is beneficial to the strength and oxidation resistance [13], and Fe decreases the melt viscosity and thereby improves the castability [14]. In the as-received 2Cr2Nb, the distribution of Cr and Nb is nearly uniform at the phase level (Fig.…”

Phase transformations during creep of a multiphase TiAl-based alloy with a modulated microstructure

“…A full assessment of this material was given in [5,19]. The comparison with the data of René 80 indicates that the TNB-V2 alloy can be an attractive alternative to the Ti-46.5Al-2Cr-2Nb-0.8Mo-0.2W-0.2Si (at.%), nearly lamellar [20]; Ti-46.7Al-1.3Fe-1.1V-0.35B (at.%), duplex [21];…”

“…Fig. 6 involves the data of two conventional ␤ phase containing alloys that were characterized in [20,21] and exhibit similar behavior. In the starting structure of these alloys, ␤ phase was preferentially distributed along the lamellar boundaries.…”