On two stages of brittle-to-ductile transition in TiAl intermetallic

The present paper has shown that the brittle-to-ductile transition in TiAl intermetallic ought to be considered as a two-stage phenomenon: (1) first noticeable increase in ductility (at T1°C) is controlled by thermally activated relaxation processes in grain boundaries. In this case, the brittle fracture type is retained; (2) following an increase in ductility (at T2=T1+ΔT) is caused by thermally activated relaxation processes within the grains (in addition to ones in grain boundaries) which lead to the transition from brittle fracture to ductile one.