FACTORS AFFECTING THE ROOM-TEMPERATURE MECHANICAL-PROPERTIES OF TICR2-BASE LAVES PHASE ALLOYS

Various effects on the room-temperature mechanical properties of TiCr2 -base alloys have been assessed in efforts to improve the toughness of Laves phase intermetallics (AB(2)). Systematic studies were pet-forme d on: (i) single-phase stoichiometric and nonstoichiometric: TiCr2: (i i) TiCr2-base ternary; Laves phases, and (iii) two-phase binary alloys containing TiCr2. In order to make quantitative comparisons among the different alloys, Vickers indentation was used to obtain hardness and ii fracture toughness values. Within the single-phase field, constitu tional defects accounted for the compositional dependencies of propert ies, and may aid the synchroshear deformation process, Ternary Laves p hases comprised of Fe, Nb, V or Mo additions to TiCr2 indicated that a lloying elements which partition to both A and B sublattices can impro ve the toughness. Stabilization of the cubic C15 crystal structure als o resulted in higher toughness values. Small amounts of the bce beta-p hase effectively reduced crack lengths in the Laves phase, and two-pha se alloys of (Ti,Cr) + TiCr2 exhibited significant improvements in tou ghness. (C) 1998 Elsevier Science S.A.