The Effects of Nb and Cr Addition on Mechanical and Chemical Properties of Cold-Rolled Ni3(Si,Ti) Intermetallic Foils

Abstract

Nb and/or Cr added Ni3(Si,Ti) as well as unalloyed Ni3(Si,Ti) intermetallic thin foils (i.e., Ni3(Si,Ti), Ni3(Si,Ti)+Nb, Ni3(Si,Ti)+Cr and Ni3(Si,Ti)+Nb,Cr) were fabricated from arc-melted polycrystalline ingots by thermomechanical process and subsequent heavy cold-rolling. Tensile property at room temperature as well as at high temperature and oxidization behavior of the cold-rolled foils with a thickness of ~200μm were investigated. The Ni3(Si,Ti) and Ni3(Si,Ti)+Nb alloys showed a single-phase microstructure consisting of L12 phase, while the Ni3(Si,Ti)+Cr and Ni3(Si,Ti)+Nb,Cr alloys exhibited a two-phase microstructure with A1 (fcc) Ni solid solution phase within the L12 grains. All the cold-rolled foils showed high tensile strength (over 2GPa) at room temperature although no plastic elongation was observed. The addition of Nb and/or Cr slightly enhanced the room-temperature tensile strength of the Ni3(Si,Ti) alloy. On the other hand, the addition of Nb and/or Cr prominently enhanced high-temperature tensile strength as well as oxidization resistance, while the addition of Cr improved high-temperature elongation.