Mechanical properties of the single-phase Ti-Zr-Ni quasicrystalline alloy at roo m-temperature

Abstract

At the composition of Ti4040Zr4040Ni2020 , a single_phase cylindr ical quasicrystalline alloy, 3mm in diameter and 15mm in length, can be fabr icated by a copper-mold casting method. Its quasicrystalline nature and structu ral homogeneity were confirmed by x_ray diffraction and transmission electron mi croscopy. According to compression and indentation tests at room_temperature, th e as_cast Ti4040Zr4040Ni2020 quasicry stalline rod has a hardness of 55GPa and a fracture strength of 542MPa. In particular, the Young's modulus (～43GPa) of Ti404Zr4040 Ni2020 quasicrystals is consid erably low while they possess a high Poisson's ratio (～048). Under monax ial compression, the Ti4040Zr4040Ni2020 quasicrystalline alloy e xhibits a highly elastic deformation capability of 125%. The cleavage fracture morphologies indicate a brittle fracture mechanism.