Barbi, NicolasDiologent, FrédéricGoodall, RussellMortensen, Andreas2012-01-032012-01-032012-01-03201210.1016/j.intermet.2011.11.001https://infoscience.epfl.ch/handle/20.500.14299/76249WOS:000299983100026Fracture toughness tests are conducted at room temperature and 923 K (650 degrees C) on SENB (Single Edge Notched Bend) specimens of three different (alpha(2) + gamma ) TiAl-based alloys. One alloy is a conventional near fully lamellar Ti-45Al-2Mn-2Nb + 0.8%vol TiB2 XD alloy. The second and third have a composition of Ti -46Al-8Ta, with a novel "convoluted" cast microstructure developed for turbine applications and a coarse near fully lamellar microstructure, respectively. The novel alloy displays fracture toughness values of 13 +/- 2 MPa root m at room temperature and 19 MPa root m at 923 K (650 degrees C); these values approach data for lamellar microstructures, known to be optimal for this class of alloy. In particular, shear ligament toughening is observed with a role of retained lamellar colonies in toughening the convoluted microstructure. (C) 2011 Elsevier Ltd. All rights reserved.Titanium aluminidesbased on TiAlFracture toughnessMicrostructureAero-engine componentsTitanium Aluminide AlloysTial-AlloyMicrocrack NucleationCrack-PropagationDislocation DynamicsGrain-RefinementPst CrystalsResistanceMicrostructureToughnesstext::journal::journal article::research article