Phase field and room-temperature mechanical properties of the C15 laves phase in the Zr-Ta-Cr alloy system

摘要

The phase field of the C15 Laves phase in the Zr-Ta-Cr alloy system at 1273 K exhibited a continuous solid solution along the ZrCr2-TaCr2 pseudobinary line and also a broad off-stoichiometric range on the (Zr,Ta)-rich side. The defect structures in the C15 Laves phase were evaluated by lattice parameter and density measurements. The room-temperature fracture toughness was assessed by Vickers indentation testing. Alloying, off-stoichiometry, and the related defect structures were shown to be beneficial for improving the room-temperature deformability of the C15 Laves phase in the Zr-Ta-Cr alloy system. The results are discussed in terms of the constituent atomic sizes on the most closely packed planes in the C15 Laves phase where shear deformation takes place.