Superplastic behavior of the novel Ti-21Al-18Nb-1Mo-2V-0.3Si intermetallic alloy with rather low density ρ ≈ 5.067 g / cm 3 was studied. The homogeneous fine-grained microstructure in the alloy, which contained three ordered phases: O (Ti 2 AlNb), B2 (Ti-Al-Nb) and α 2 (Ti 3 Al), was produced by thermomechanical processing. It included the hot isostatic pressing at 1080°C (P = 140 MPa for 6 h), two-step quasi-isothermal forging at 870 -1060°C, and pack rolling at 930 -950°C. The fine-grained alloy exhibited high superplastic elongations δ > 230 % in the temperature range of 875 -1000°C and at an initial strain rate of 4 × 10 −4 s −1 . The maximum elongation δ = 958 % was obtained at 960°C. Microstructure analysis revealed that maximum superplastic elongation was obtained when material had approximately equal content of the main B2-and α 2 -phases suggesting that the B2 / α 2 phase boundary sliding plays an important role during superplastic deformation. Deviation the Burgers orientation relationships: (110) B2 // (0001) α2 , [1-1-1] B2 // [1-210] α2 pointed out to extensive grain rotation during superplastic flow. The deformation induced grain growth testified to grain boundary migration. Besides, the signs of the O→B2→α 2 phase transformations were also observed after testing at 960°C. The minor content of the O-phase in the Ti 2 AlNb-based intermetallic alloy was present at 960°C in the (α 2 + O)-lamellar structure. Crystallographic orientations between the α 2 -and the O-phases were found to be (1010) α2 // (110) O , [0001] α2 // [001] O .

The hot deformation behavior of Mg-12Gd-1MM-0.6Zr (wt.%) magnesium alloy was tested by Gleeble-1500D hot simulator with reduction of 60% and strain rates from 0.001 to 1 s−1 at the temperature range from 753 to 793 K. The results show that the flow stress is influenced by both, temperatures and strain rates. At constant temperatures, flow stress is increased with strain rate, while at constant strain rates, it decreased with temperature. The constitutive equation of Mg-12Gd-1MM-0.6Zr alloy during hot compression was constructed by the linear regression analysis. Average activation energy and stress exponent were 227.94 kJ/mol and 2.87, respectively. The processing map was plotted and analyzed via the dynamic material model. The most proper ranges for hot deformation temperature and strain rate were found to be 763 to 783 K and 0.01 to 0.1 s−1, respectively.