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 n oticeable increase in ductility (at T(1)degrees C) is controlled by thermal ly activated relaxation processes in grain boundaries. In this case, the br ittle fracture type is retained; (2) following an increase in ductility (at T-2 = T-1 + Delta T) 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. (C) 1999 Elsevier Scie nce Ltd. All rights reserved.