Variation of the phase distribution in a Ti-44Al-2Mo alloy by annealing: Influence on its strength and ductility

Microstructural stability of γ-based TiAl intermetallics containing β phase

“…In addition, since the B2 phase is a relatively hard phase [9], the strength of the alloy remains sufficiently high even when tested at 700 8C, as confirmed in Fig. 11(b), where we see that after annealing at 1000 8C/768 h the yield stress of the alloy at 700 8C is close to 500 MPa.…”

“…On the other hand those elements have different effects on the stability of two phase (a 2 Cg) lamellar microstructures as well as on the temperatures required to obtain them. Thus, ternary elements like Mo have been shown to stabilise the B2 phase modifying the microstructure of the alloys by producing a distribution of three phases (a 2 CgCB2) [9]. Also, it has been confirmed that the addition of W hinders the formation of two phase (a 2 Cg) lamellar structures during processing or subsequent annealing [10].…”

Thermodynamic assessment of the Al–Mo system and of the Ti–Al–Mo System from 0 to 20at.% Ti

“…Hansen and Raman [48] showed that alloys of composition 26 at.%Tie64 at.%Ale10 at.%Mo, 16 at.%Tie68 at.% Ale16 at.%Mo, and 12.5 at.%Tie75 at.%Ale12.5 at.%Mo were all single phase h-(Ti,Mo)Al 3 at 1198 K, and the h-(Ti,Mo)Al 3 phase was found to extend to Mo compositions as high as 20 at.%Mo and Al compositions as low as 62 at.%Al at 1198 K [48]. Eremenko et al [49] confirmed the large homogeneity range of the h-(Ti,Mo)Al 3 phase at 1573 K, and Abdel-Hamid [50] Das et al [12] showed that at 1448 K, the g-TiAl phase contains z1 at.%Mo at 52 at.%Ti and z3 at.%Mo at 48 at.%Ti whereas Morris et al [3] measured the Mo content of the g-TiAl phase in equilibrium with the a 2 -Ti 3 Al and b 0 phases at 1173 K and 1473 K as 1 at.% Mo at 51 at.%Ti and 1.5 at.%Mo at 53 at.%Ti respectively. Kimura and Hashimoto [51] measured the Mo content of the g-TiAl phase in equilibrium with the a 2 -Ti 3 Al and b 0 phases at 1473 K as 0.5 at.%Mo at 50 at.%Ti, which is much lower than that measured in the work of Das et al [12].…”

“…In fact, the partial isothermal sections at 1448 K of Das et al [57] and at 1573 K and 1473 K of Kimura and Hashimoto [51] show only the a phase. However, Morris et al [3] claimed to also have the a 2 -Ti 3 Al phase at 1473 K. The ordered b 0 phase was first determined by Böhm and Löh-berg [58] in alloys within the composition range from z60 wt.%Mo to z30 wt.%Mo at 50 at.%Ti which were heat treated at 1073 K and then quenched. Singh et al [59] performed Rietveld refinement of X-ray and neutron diffraction data from an alloy of composition 50 at.%Tie25 at.%Ale25 at.%Mo which was homogenized at 1273 K and furnace cooled.…”

Effect of alloying and aging on morphological changes from lamellar to equiaxed microstructure of α 2+γ titanium aluminides

“…pct). [13][14][15][16] It is well known that the addition of Nb and Mo stabilizes the ␤ phase in these alloys, [17][18][19][20][21][22][23] but the effect of these additions on the stability of lamellar microstructure is unknown.…”