Microstructural and high temperature deformation characterization of Ti–45Al–3Nb–(Cr, Mn, Mo, Sc) alloy

The effect of complex microalloying by combinative additions of Nb, Sc, Mn, Cr and Mo to the directionally solidified Ti–45Al alloys on microstructures and mechanical properties has been examined in the present study. It is shown that a respective microstructure of fully lamellar for Ti–45Al–3Nb and Ti–45Al–3Nb–0.5Sc and basket weave type for Ti–45Al–3Nb–2Cr–2Mo–1Mn–0.5Sc were observed. The high temperature strength of Ti–45Al–3Nb alloy is improved via dispersive strengthening effect of fine Ti3(Al,Sc) dispersoids and solution strengthening effect from the other alloying elements. Enhanced ductility of Ti–45Al–3Nb alloy was achieved by Cr, Mn and Mo combinative additions.

Research highlights▶ Complex microalloying increased remarkably the high temperature strength of Ti–45Al–3Nb alloy. ▶ Strength increase was attributed to microstructural refinement, dispersive and solution strengthening effects. ▶ The ductility of Ti45Al3Nb was remarkably enhanced owing to improvement of inhomogeneous distribution of electron cloud.